India: Epic AMR water conveyance project

Direct by Design

AMR water supply drive

An epic tale of long distance TBM excavation

Underground in Action U

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Direct by Design

TunnelTalk Annual Reviews Since its launch in 2008, TunnelTalk has charted the progress of major projects and developments in the international tunnelling and underground construction industry. As a record of these achievements, our Annual Review magazines provide a research resource to recall who, what, when, where, why and how the underground infrastructure of our nations has been built and is now being operated. Reporting the experience of each major project provides valuable information for clients, consulting engineers, contractors, manufacturers and materials suppliers.

Connectivity beneath mountains, under the sea, between countries and across cities was the focus in Europe for the past decade. TBMs, immersed tubes, drill+blast and openface excavations were supported with every tool possible to achieve success. TunnelTalk has followed leading projects through their journeys.

First breakthrough for

Auckland mega-TBM

Finding a formula for delivering

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high speed rail in Brazil

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New era begins for ITA at WTC 2019

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Section 2: Galeão Airport (RJ) to Barra Mansa/Volta Redonda (RJ)

103.1

8,253

80

26%

24%

50%

Section 3: Barra Mansa/ Volta Redonda (RJ) to São José (SP)

210.4

10,923

51.9

6%

22%

28%

Section 4: São José dos Campos (SP) to Guarulhos Airport (SP)

61.8

3,650

59.1

11%

21%

33%

Section 5: Guarulhos Airport (SP) to Campo de Marte (SP)

21.8

2.313

106

81%

0%

81%

Section 6: Campo de Marte (SP) to Viracopos Airport (SP)

75.4

6,565

87.1

28%

22%

50%

Section 7: Viracopos Airport (SP) to Campinas (SP)

23.2

1,558

67.2

10%

7%

17%

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inspiring futuristic solutions

flushing toilets, watering gardens, washing cars, washing clothes, and everything but drinking and cooking.

Underground high voltage electricity cables: London leads the way with hundreds of kilometres of high voltage cable tunnels under the city (see p49). TBM manufacturer Herrenknecht won the award for innovation at the bauma trade show in Munich in April 2019 for its development of high-speed micro machines to create the underground links for carrying wind farm cables from the North Sea where it is generated, to the south of Germany where it is needed (see p88).

Create more multi-use underground infrastructure: Examples of such infrastructure includes the SMART tunnel in Kuala Lumpur that is both a stormwater conduit and a double deck highway for when the stormwater facility is not needed; the water, gas, sewer, ground water conduits under Ashgabat, Turkmenistan; and large diameter TBM tunnels to accommodate both road and metro links in the same tubes. More stormwater facilities that could have a SMART tunnel concept are needed to protect sinking cities including Jakarta, Manila, Mexico City, Bangkok and many others.

Underground living in Coober Pedy, Australia

Nuclear waste: Progress - with urgency - the desperate need for viable, safe, long long-term disposal or storage of low-, medium and high-level nuclear waste.

This should be a universal imperative rather than a national issue to solve. The engineering industry is prepared and able to build such facilities. It is the political will and responsible leadership that is lacking. Another suggestion is to build nuclear power reactors underground in closed, contained environments.

Caverns large enough for the purpose already exist in the impressive scale and excavation of hydro power machine halls.

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www.TunnelTalk.com

mega BM

Build down rather than up in dense urban and city environments

*Source: Halcrow/Sinergia TAV Capital Cost Final Report (Sept 2009)

TunnelTalk AnnuAl Review 2013

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www.TunnelTalk.com

TunnelTalk ANNUAL REVIEW 2019

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BRENNER BASE TUNNEL, AUSTRIA – ITALY

Annual Review

2020

2019

www.TunnelTalk.com

Contractors: 1 x Gripper TBM: Consortium H33 Tulfes-Pfons 3 x Double Shield TBM: Consortium Mules 2-3 2 x Single Shield TBM: Consortium H51 Pfons-Brenner

Into

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Direct by Design

Annual Review

2020

The new brenner base tunnel represents a next level of trailblazing hard-rock-tunnelling. With a total length of 64 km and maximum overburden of 1,300 meters this high-impact project sets new records.

Six project specific engineered Herrenknecht hard-rock-machines are involved in the hardest mission worldwide. Empowering our customers to push the limits. herrenknecht.com/bbt/

Direct by Design 10th ANNIVERSARY TUNNELTALK ANNUAL REVIEW 2019

PUSHING LIMITS WITH VIGOROUS ENGINEERING

2021

Into

2020

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Hard copies are available by contacting TunnelTalk@TunnelTalk.com

GLOBAL CONNECTIONS

Intricate excavation upgrades London metro station

Fo o ne n No way

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Speaking to TunnelTalk from Brasilia, Franca said: “Last time the concession was auctioned on a single design-buildsupply-operate model with all the risks of construction centred on the private sector. The cost-risk ratio was deemed [by private investors and construction companies] to be very high. So what we have done is separate the project into two elements.”

The first is a concession to operate the system, develop the trains and provide the operating technology at a minimum of BR$70.31 (US$35)/train/km).

Assuming that a concessionaire to operate the system is identified, the second

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Global dilemma of nuclear waste management

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FOCUS: NUCLEAR WASTE MANAGEMENT

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MEGA PROJECTS

Shani Wallis, TunnelTalk

Digital editions of the Annual Review publications are available on our digital magazine p atform

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TunnelTalk ANNUAL REVIEW 2020

Fehmarnbelt Denmark-Germany sea link approved in Denmark, 2014

here was only one story in 2020 Covid-19. There is no country, no In Canada, the largest of a number of inhabited island, no continent, no hydro projects under construction is the South America community, spared the spread of the infection.

1,100 MW BC Hydro Site C project on the South America is one of the fastest growing For the underground construction Peace River, which requires the construction regions for hydropower development in the industry, all projects have had to of two 10.3m i.d. concrete-lined diversion world, adding close to 4,855 MW in 2018, cope with the imposed pandemictunnels of 700m and 800m long to allow despite the growing challenge posed by control lockdowns and regulations. construction of the dam. Excavated climate variability.

Social distancing, occupational health Brazil accounts for about two-thirds using two Sandvik 115 tonne MT 520 restrictions and supply chain disruptions roadheaders, the first tunnel broke through of installed capacity. One of the largest have caused inevitable production and in June 2019 after 10 months of excavation, dams in the world, the Belo Monte Dam Crossrail excavation progress slow downs and cost increases. and the second followed in July. Focus complex on the Cingu River in the north ofFinal TBMs breakthrough on Follo Line, finalised, UK, Nonetheless, projects have continued and is now on lining and finishing the tunnels. the country, recently commissioned a newNorway, February 2019 June 2015 that is a credit to the managers and teams The CAN$1.75 billion civil works package turbine, number 18, to bring the capacity of of workers who have carried on. is being undertaken by Peace River Hydro the installation to 11,233 MW. Belo Monta Some construction companies have Partners, a joint venture between Acciona could be the last mega project in Brazil, taken matters into their own hands to Infrastructure and Samsung C&T and is according to the IHA, as the country moves manage testing and isolation strategies. towards a more decentralised network of expected to be complete by 2024.

In Malaysia, as an example, the MCCWork is also continuing on the La renewable energy.

Gamuda JV working on the Putrajaya The 2,400 MW Ituango project in Romaine project for Hydro-Quebec with the Line 2 of the Klang Valley MRT in Kuala final 245 MW La Romaine 4 element due Columbia is the largest in the country Lumpur, established its own Covid-19 for completion in 2021 bringing the total and, when complete, will meet about 18% testing laboratory for its workers. It is a capacity of the facility to 1,550 MW. The of electricity demand in the country. The laboratory established within weeks to 824 MW Muskrat Falls project on the Lower project was hit by a major flood disaster in conduct its own polymerase chain reaction Church River in Labrador and the 695 MW 2018 (see p31).

(PCR) test for the infection and in response Projects are underway in Peru, as Keeyask project on the Nelson River in to two constructions sites being closed Manitoba are also in the works. In Alberta, part of a Government commitment to down by the government after hundreds of construction of the 75 MW Canyon Creek become energy self-sufficient by 2024, workers contracted the virus. The JV has a pumped storage project, including a 7km as well as in Paraguay, Ecuador, Bolivia workforce of some 20,000 personnel at all x 2.5m i.d. long headrace, has been and Guyana.

Ground freezing assists Hallandsås railway levels, including 7,000 labourers working In Chile, the 531 MW Alto Maipoexcavation to breakthrough, Sweden, June 2010 approved. Renewable energy accounts across the 50km Line 2 alignment. for about two-thirds of power generation project is the largest in the country and The other global reality has been the in Canada, based largely on its significant will be one of the largest underground work from home where possible. While hydropower facilities in the world with more hydro resources. these have been understood and managed Although the USA remains one of than 70km of tunnels and two powerhouse Peter Kenyon, TunnelTalk through a surge in the development and the largest producers of hydropower, caverns. It comprises a cascade of two improvement of online video and group new projects are slow to progress with run-of-river plants – the 264 MW Alfalfal meeting systems, the impact on empty n September 2014, the 14.5m diameter always planned to do everything very compared to the more usual 30-35%, to investment mostly focused on retrofits of 2 and 267 MW Las Lajas installations. A city centre offices has been devastating Herrenknecht EPBM brokethrough at carefully mitigate such risks. “As it happened we had financial restructuring in 2018 saw theat the start. We went through existing facilities, despite the Department for all the support services including the the end ofsigning its first of drive for the NZ$1.4 live trials of running the TBM in full EPB very little problem with clogging. At the start a new construction contract of Energy saying 50 GW of new capacity commuter trains and metro services.

Waterview highway connection in mode and found the maximum required of the drive we had a slight challenge after with Strabag, after termination of the could be added by 2050. Somebillion 35 GW A report in The Economist magazine Auckland, Zealand. we went through the portal headwall, where original contract with Hochtief andwould CMCbe di about 1 bar at the crown, but on of this would be pumped storage, such New reported that ridership of the Subway The project comprises 2.4km of twinincludes a machine some clogging was experienced, most likely Ravenna.

The new contract the of this size that means about as the planned 400 MW Gordon Butte fter previous aborted attempts element is construction of the line, and it will Peter Kenyon, TunnelTalk in New York City had fallen by 75% running tunnels as part of a wider 5km x 2.5 as a result of a mixture of concrete, steel excavation 18.5km of tunnels asbar wellat the invert. The machine has project in Montana. to auction the country’s first ever be the Brazilian public through public funding compared with typical daily ridership, with 3-lane highway that completes the structures the design capability to reach a maximum fibres and soil, but during the remainder as project construction of the intake New developments in Mexico have high speed rail link, the Brazilian that will pay. the agency losing $200 million/week due Western Bypass andsteel should provide thrust of 300,000kN but we managed the drive we had no real issues in this and a 5km pipeline.

Strabag had also been slow to materialise,city’s despite 12 TunnelTalk ANNUAL REVIEW 2019 of www.TunnelTalk.com Government was forced into a strategic “Civil works will be the responsibility to lost fare, toll and subsidy revenues. much-needed relief to the congested city in through regard,” said Hanke. been contracted 2012 tothe first drive at about 60,000kN,” ambitious goals by the Government to previously rethink. Following the last failure to find of the Government,” said Franca. “We Subway services were reduced by 40%, centre and the harbourtwo-thirds bridge. Theofproject said Simmons.

Water ingress at rates of up to 20 litres/ excavate the underground promote renewable energy. a bidder, a new request for international believe that by separating construction and long promised capital projects have been notable forwatercourse hitting all schedules out by Other than the tail seal issues, sec in some places, and at pressures of and set powerhouse works, In Central America, severalis smaller qualifiers was issued, and this time the operation, and deciding to finance the full delayed or suspended and up to 8,400 delivery team that incorporates the Newandeverything up to 3 bar, especially through sections of totalling 46km of tunnels shafts. went smoothly. The geology projects are underway with a a number Government is confident the 511km route amount of construction from public funds, agency workers were predicted to lose Zealand Transportation Agency as owner, was as predicted, comprising a mix the harder layers of Parnell Grit, required of governments developing ambitious Four open gripper TBMs were used to that would link the major airport cities of we have a good system in place.” and its tunnel contractors McConnell Dowell, of sand and silts of the Taurunga careful balancing of face pressure.

Rio de Janeiro, São Paulo and Campinas To make the operation concession Obayashi and Fletcher, which are together Group, unweathered weak siltstone Best excavation performance in a will actually attract bids rather than more attractive, the Brazilian Government 6 www.TunnelTalk.com TunnelTalk ANNUAL REVIEW 2020 known as the Well Connected Alliance. and sandstone of the East Coast Bay single 24-hour period was recorded at expressions of interest. raised its proposed stake from 30% to 45% The machine was powered up at the Formation (ECBF), and with a small risk 29.8m, with a best monthly advance of In all respects the selected route is in the Special Purpose Entity (SPE) that start of the first drive on the very day that of meeting much harder (up to 150MPa) 452m. “We expect to complete the second a challenge. It rises from sea level at Rio will be formed with the successful private had been planned nearly two years before, layers of cemented sandstone of the drive substantially faster as a result of de Janeiro, passes through the Sierra enterprise operating consortium. With and first breakthrough was also achieved Parnell Grit type. Abrasive wear to the 19in lessons learned from the first drive about das Araras mountains, and reaches an the first phase estimated at BR$7.6 billion on schedule (Table 1). cutters, manufactured for Herrenknecht the geology, machine capability, and elevation of 700m at the plateau on which (US$3.8 billion), and with RS$5.4 billion This is despite the fact that four in the USA and selected for their abrasion knowledge gained about optimised soil São Paulo is built. Nearly 18% or about (US$2.7 billion) in BNDES loans already weeks were lost during the drive for two resistance qualities, remained within conditioning,” said Hanke.

90km of the alignment requires tunnels, secured, this implies a cash investment of unscheduled stops. Construction Director parameters, as did anticipated water Progress through what was predicted while a further 21% (107km) comprises approximately BR$1.25 billion (US$626 Stefan Hanke told TunnelTalk from New inflow rates. to be the most challenging section of the bridges and viaducts. million) from the successful consortium Zealand: “We had a bit of a slower start On all occasions the team was alignment through the saturated silts of Halcrow of the UK (a CH2M-Hill (based on a 55-45 equity split with the SPE). than we thought while we monitored the able to find competent ground in which the Taurunga Group, progressed at an company) and Sinergia of Brazil produced “We [the Government] have no fear performance of the TBM and checked to complete maintenance. As a result, average 10 rings/day, but was made more detailed alignment studies, preliminary of taking on the risks of this project,” settlement levels, and there were two no hyperbaric interventions proved complicated towards the end by the fact estimates of cost and passenger said EPL President Figueredo. “We are unscheduled stops to replace the tail seals necessary, said Hanke. trafficwill projections. report, seen TBM be turned The into second drive by sure that there will be demand for trains.” after we discovered leakages. That put us Fears about possible clogging at the TunnelTalk, makes forplates sobering reading Brazilian taxpayers will get their substantial across greased steel back a month, but we still managed the TBM cutterhead and in the mixing chamber for potential investors and construction investment back through a mix of ticket September breakthrough, as planned, so – a common experience in Auckland for consortia that under the old finance- revenue, earned from owning a 45% share we remain fully on programme.” previous mechanised drives – turned out build-operate model were expected to of the SPE, plus concessionary fees earned “We did not rush to make metres,” to be ill-founded. This is attributed to the bear all financing and construction costs. during the 40-year life of the concession. said Ian Simmons, Tunnel Construction design of the TBM, which incorporates Critics argued, and still do, that the Under the terms of the latest auction, Manager on the NZ$1.4 billion project. We a larger than usual opening ratio of 45%, passenger figures were overstated and the successful consortium will have to: the construction costs understated.

• guarantee a 99 minute service between table 1. Project programme milestone targets The BR$28 billion (US$13.7 billion) São Paulo and Rio; predicted construction cost (in 2008 • must not include any rail partners that Completion of the first bore September 2014 figures), proved too much for the have suffered a fatal accident in the Turn around period Three months international financiers and construction last five years (down from the 10-year consortia that expressed an interest in the qualification of the last auction); and Completion of all tunnelling September 2015 last procurement process. Ultimately, none • must make 60% of seats available for a Contractual delivery of the finished tunnels April 2017 of the groups, from Korea, Japan, Germany, price of less than BR$200.

France and China, elected to submit a bid.

If the project goes ahead, tunnel This time, Hélio Franca, a Director of construction costs are estimated at more 7 8 www.TunnelTalk.com TunnelTalk 2014 the newly-created State AnnuAl company Review that than BR$1 forms the lynchpin of the new strategy Fig 1. 511km route of the Rio-São Paulo-Campinas HSR for advancing high speed rail in Brazil, is confident things will be very different.

Table 1. Section distances and tunnel and bridge percentages Both he and his colleague, Bernardo Figueiredo, are former senior executives Length Cost (BR$ Cost/km % % % tunnels of Brazil’s National Land Transport Agency (km) million) (BR$ million) tunnel bridges & bridges (ANTT), the Government organisation that Section 1: Barão de Mauá (RJ) has been responsible for developing high 15.2 1,367 90.2 22% 34% 56% to Galeão Airport (RJ) speed rail since the idea was first conceived.

North and Central America

Europe united

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ransport Ministers of seven European Member States and all 10 European Coordinators or representatives of major cross-boarder Dipl.-Ing. Roland Herr, reporting for TunnelTalk corridor projects in Europe attended a two-day congress in Innsbruck in March 2015 to discuss the international comprise significant underground and developed between Finland, the Baltic mega projects planned to improve inter- tunnelling works.

States, Poland, Germany, the Netherlands connectivity across the continent. and Belgium. The proposed strait crossing “One of the most important 1. Baltic-Adriatic Corridor fixed-link tunnel between Helsinki and fundaments for securing a unified Europe This 2,400km long corridor will provide better Tallinn is part of this corridor. is the investment in a modern high- access to Baltic and Adriatic seaports for performance infrastructure for land- the economic centres in Poland, the Czech 3. Mediterranean Corridor he world has been living with a nuclear which generates its own volumes of nuclear Shani Wallis, TunnelTalk their jobs. The reality is shared by public Franklin Roosevelt in the USA in the 1930s based transportation,” said Prof Konrad Republic, Slovakia and Austria. The main One of the well-known missing links on this he next major phase of tunnelling on • A short extension of the twin main environment forPatrick more than 75 years,TunnelTalk and contaminated waste. For the purposes Reynolds, transport agencies in other major capital to recover from the Great Depression Bergmeister, CEO of the Brenner Base missing links are the cross-border sections 3,000km connection for high-speed trains the Brenner Base Tunnel has begun for defence, for power generation of storing or disposing of waste, the thermal base tunnels by about 5km at the and the Semmering and Koralm railway cities hit hard by the pandemic. that started in 1928. Such a programme Tunnel project developer, BBT SE, and from the western Mediterranean region to the in the Alps between Austria and The consensus among scientists, and in the fields of science, research and heat generated by nuclear waste is as Ahrental adit area. tunnels in Austria for the Alpine crossing.

A consensus of opinion is that, even provides wages rather than handouts and of the Innsbruck conference, Ukrainian border with Hungary and following Italy with the Strabag and Salini Impregilo users of nuclear materials and medicine. the amount nuclear much of an issue as its radioactive organizer level. engineers, Drill+blast excavation started in Asaddition to a of few short material lengths of the main Construction on both Austrian projects started if it were possible, a return to normal leaves something worthy and tangible as in ofcooperation European the coastlines of Spain and France, crossing JV making an official start of excavation September, and a TBM drive is scheduled the generalwith public,the is that the safest place and the waste it at generates has grown Nuclear material can emit temperatures tunnels adit junctions,” said Lochmann. in April 2012 and April 2011 respectively. will be different. The need for 9am-5pm a legacy.

Commission.

The trans-European the Alps to the east through Italy, Slovenia and on its 55-month, €377.3 million contract to launch in mid-2015. for the storage of nuclear Network waste of all levels exponentially, the and controlling the build-up Thelong-term portionsmanagement of exploratory200-250ºC tunnel commuting to a central office five days a An interesting point in The Economist known as TEN-T, is a basic Croatia, is the new cross-border Lyon-Turin 2. North Sea-Baltic Corridor for the mega project’s Tulfes-Pfons Lot. The potential for design, of the spentexcavated and decommissioned nuclear of heatinin the management of wasteforis Transport, a is underground. to date were undertaken week has proven to be unnecessary and report is that where Covid-19 caused a plan for excavation addressingand theconstruction most important high speed rail project between France and Cross-border operational systems for road Located at the Austrian end of the €8.6 Baseline design of underground fuel and contaminated materials two sections, one remains at eachanend.significant At the design consideration. the need for international travel for business reduction in New York Subway ridership bottlenecks and cross-border projects.

Italy which runs 57km in twin tube tunnels. and railway need to be modernized and billion scheme (in 2012 prices), the Tulfes- In the overall project layout, the issue that lies interminably in many north Austrian stalled end, the Strabag/PorrThe JVgreatest volume of civil-use nuclear waste repositories is tremendous.

Brenner meetings and conferences is equally of 75%, during the Great Depression the Nine corridors are setwhich tocreated improve eastUnderground spaces by SCL ready Pfons Lot calls for a total of about 38km of Base Tunnel scheme comprises The UK, commissioned the for nuclearancountries. is generated by the nuclear power completed drill+blast excavationwaste of the considered expendable by the managers fall was 12% in the years 1929 to 1933. west and north-south connections for power of fully the inner architectural and M&E finishes drill+blast and TBM excavation. world’s first operational nuclear It is difficult to investigate the scale of at industry. section to the first adit junction Ahrental.According to the WNA, there are 440construction exploratory/drainage/service tunnel running of many companies. The shutdown There are differences with the current crisis movement of both freight and passengers.

At the same time, the Strabag between, and slightly below, the two use,main waste generation and management At the southern Italian end,in theoperating longest nuclear power reactors today in 31 plant at Calder Hall at Windscale in England and much reduced level of air travel and and the unemployment it is generating, The cost of developing the TEN-T Core Salini-Impregilo, Consorzio Cooperative running tunnels for the full lengththeof nuclear defence industries, which from the Aicha countries. bore advanced (Aica) These operating reactors have a in 1956 and currently has 15 operating the exploratory highway traffic is a welcome reprieve for but a common denominator is the lack Network requires an estimated €500 Costruzioni CCC, Collini Lavori JV was project. The 8.1m i.d. main runningconsensus all around world assumes, totalTBM. installed electricity producing capacity nuclear power reactors, had a radioactive using a 6.3mthediameter double shield tunnels for air quality and the natural environment. of national resilience preparedness. Chief billion, with €250 billion to be spent on awarded €300 million construction of are 70m apart, linked by cross passages despite international limitation is off-line of 2.653 The 10.5km bore,agreements, which started and trillion kWh and represent about waste inventory of 133,000m3 in early 2019.

Exactly how the world will be shaped in the among them is a lack of investment in removing the main bottlenecks up to the Eisack River undercrossing of the every 333m, and have multifunctional Underground facilities to hold these existing still significant.

The same for peacetime of the world electricity generation. reached the data Mauls (Mules) adit 10.5% between future, and as a direct result of the 2020 education and vocational training. Training 2020. These Core Network alignment located at the Italian end of the emergency stations, with accessindustries and nine projected volumes Corridors of nuclear waste be researched and reported main running tunnels, with was excavated to the canthe pandemic, is now the focus for visionary and retraining of those who have lost jobs project near the town of Franzensfeste surface, at 20km intervals (Fig 1). the assistance of international “The consensus... is that the require labyrinths of expansive scale.

by SELI, as part ofassociations the JV with Pizzarotti, civil and social engineers. across the globe will not be a short redress.

(Fortezza). Contract scope comprises The question as to why these underground including the IAEA, Berger, International Bilfinger Alpine Atomic Meyreder,safest Beton– place for the storage The geology on the alignment In the shorter term, the task is to shape There is the question of money to lead construction of the two Base Tunnel comprises quartz phyllite, slates,Energy facilities for the long-term storage of nuclear Association of the United Nations and and Societa und Monierbau, Jaeger, Collini gneiss a social and economic recovery. While a construction investment recovery. So of nuclear waste of all main tubes for a total of 4.3km and and granites with several identified waste are not in construction or already the World Nuclear Agency (WNA). d’Acqua.

Italiana per Condotte billions, even trillions, have been spent many nations have expended huge financial two connecting tunnels to the existing faults and anticipated hydrogeological constructed is a question of politics. While levels is underground” The WNA, To an extend agency the headquartered exploratory tunnel in on supporting businesses and workers capacity to address the consequences of Brenner Railway. As well as the River challenges. “So far, a total of aboutin12km the IAEA and the WNA coordinate expertise the ofUK the andTulfes-Pfons with a membership of Lot, the Strabag-Salini through loans and furlough payments and the pandemic, compounding already high Eisack undercrossing, the route passes the exploratory tunnel has been excavated international companies and organisations, Others are being planned, are in from across the world to inform global policythe growing numbers of unemployed, what national borrowings, and taking advantage under the Brenner Motorway, the state along the main axis of the project promotes in a wider understanding of construction, or ready to come online. These making for the management of nuclear waste, many agree is needed is an infrastructure of historically low interest rates. As an highway and the Brennerand Railway with aof Herrenkencht nuclear energy by producing authoritative include the first floating nuclear power plant, their member nations all make their own prepared specifically forforunderground engineer as founder Wallis, TunnelTalk constructionShani led recovery similar to the example, Chancellor of the Exchequer information, Fig 1. Latest schematic of the 55km long developing common industry the Akademik Lomonosov in Russia. “It is decisions and policies. byvery thelow ITArock in overburden.

AG. This ranged from his first underground New Deal programme of public works the UK, as oneconstruction of the globalcontracts G7 nations, While the scale and values theopen-face two In the case of the UK and other positions, sharing best practices, and one of the first of the new type of smaller Brenner Base Tunnel from the Innsbruck collaboration with FIDIC. job working on ofthe Big John projects spearheaded by president Presidentandannounced in November 2020 that the UK he first woman the first lots are substantial, the packages are to be contributing to the energy debate. reactors that will bring nuclear energy to democratic government countries, the Portal in Austria (left) to the •£394 Approval theyear proposal Switzerland, will borrow billion inofthe 2020, by Iran to machine of the early 1970s in North president from China was elected to followed larger contracts for the ofFortezza South Portal in Italy (right)For the management of civil and military smaller grids and for different applications,” hosting of an underground storage facility a newGDP Working Group on by the three through the development machines 19%and or one fifthestablish of the nation’s (gross A city without a lead metro system is likened the International Tunnelling Brennerwith Basis Tunnel has to be pgrade on a voluntary basis. Bank This isStation a use waste, there are four main categories; said John Lindberg of the WNA. Design and Construction ofproject.

Shafts. The client, to cope increasingly demanding of interchange • Development of a sprayed concrete Sebastian Kumpfmueller, Senior domestic to a skyscraper withoutSpace an elevator Underground Association (ITA) for the product) and the highest ever in(BBT-SE), a JV of the Austrian and Italian promote low level, intermediate level, high level Countries building their first nuclear notoriouslyondifficult Approval will and publication the process London to Underground radial joint, without connecting peace time.•Borrowings continue to be of reports geological and logistical challenges.

SCL Engineer & Senior Associate, coming three years during the 2019 World rail companies, ÖBB and TFB respectively, from ain national waste and spent nuclear fuel. Examples power plants to add to the 31 countries and market andcoming developments other Working Most recently, developments include network the UK government has been an reinforcement, to eliminate the need of through the recoverybyyears Dr Sauer & Partners Tunnel Congress at its 45th Annual high General plans to start these final systems and leading to adesign state of inertia. of low level waste include radioactively with nuclear power generation include the perspective, Groups andnation by theequalling three Committees of procurement sophisticatedfor electronic exercise in intricate and construction workers entering the face; withItaly underlying debt for the Donal Kelly, Tunnel Manager, Assembly of the Association in Naples, three largest lots in 2016, that saidincrease Simon the safety and the thankfully rare occasion contaminated clothing, equipment and tools United Arab Emirates, Belarus, Turkey and the Association – ITACUS, ITACOSUF technologies ofIt is underground structures in the of heart • Optimised SCL lining thicknesses to Dragados SA UK & Ireland In a close result, the 78 Member97.57% Nations of GDP by 2025/2026. This is inLochmann, the Head of Communications disasterscentre in the nuclear and medical tubes, swabs and hypodermic Bangladesh. There are plans also for the first accidents and ITAtech. performance of TBMs and contribute to of theand financial of theindustry city and reduce the risk of fallouts and improve of the Association voted 30 to 32 addition to elect to the future financial uncertaintyfor BBT-SE. thatwithin concentrates political attention and moves syringes. Intermediate waste comprises schemes in Egypt and Uzbekistan.

New publications include from reduced excavation costs. a complex of existing underground construction cycles; the UK fully outside the European Union, Jenny Yan of China, with Eric Leca ofofFrance The Tulfes-Pfons awarded to presentation, debate. The all disaster of the resins, chemical sludge and metal nuclear “Of all the used fuel discharged from the infrastructure, Working Group 2 new guidelines for the In anLotengaging keynote of which hadChernobyl to remain in • Change of proposed hand mining workforce to access close to the face and as ofYan 1 January 2021, and standing alone proving a formidable fellow candidate. has four areas station throughout in 1986, and the disaster of the fuel cladding, as well as contaminated reactors, about one third has been recycled, power design of segmental tunnel Strabag-Salini linings; from Impreglio Pietro Salini, CEO of ofSalini Impregilo, operation the works. operations to sprayed concrete linings avoiding the need for a temporary SCL on the international stage. takes over from President Tarcisio Celestino tunnel plant after the catastrophic materials from reactor decommissioning. with the remainder kept in storage pending Fukushima Working Group 5 a client’s guide forworks: high emphasised the need to attract young sealing layernetwork of the face.

The stepped SCL In apower successful collaboration between for improved workability; Core corridors of Brazil and is joined by four new There Vice are also the political decisions• A new 15km section of exploratory of March in Japan, raised public High level waste is the highly radioactive either reprocessing or final disposal,” said tsunami pressure compressed air work; and from professionals to the industry and addressed application used the robotic concrete Dr Sauer & 2011 Partners, Dragados and the • Application of 3D ground modelling; and lining needed to approve major infrastructure for advanced land-based Presidents with Lars Babendererde (Member tunnel; had the direct effectmanagement of leading materials produced as a by-product of the Lindberg. “The reprocessing of nuclear awareness Working Groups 14 and 15 a joint report the topic of risk aversion and unrealistic equipment with the the excavator Londonand Underground project • Adoption of a risk-based approach to spraying projects connectivity across Nation Germany) as first Vice President; and as part of a Covid New Deal• A 9.1km long safety/rescue tunnel; peoplethe andupgrade Government of Germany reactions that occur inside nuclear reactors materials is a well-established practice in the team, on handling, treatment and disposal of competition in the contracting sector, saying breaking European out the SCL lining toe for the project began with design and construction. recovery. continent Randy Essex (USA), Arnold Dix (Australia), and As so often happens, start• Two large connecting tunnels totalling close eight of its 17 million nuclear design-build reactors and takes one of two forms with spent France, Russia and the UK and there are to award excavation materials. that the continuing attempts by owners of the £642 During excavation, the exterior of several joint preparation and cleaning (Fig 2). This of so-called shovel-ready projects are Giuseppe Lunardi (Italy) as co-Vice Presidents. somenew 9km intolength; andonto the contractors, that are to begin of reactor fuel considered to be waste when innovative reactor designs being developed immediately The ITAtech Committee produced shift risk contract and in July 2013decommissioning and had progressed existing London Underground assets were innovation is a significant advancement for delayed, postponed or cancelled at the “The biggest certified Newly elected members of the Executive by the endcompletion of 2022. of the civil works exposed. No internal propping within existing the SCL tunnelling industry by making the accepted for disposal. that can use up to 97% of the fuel, compared them reports on aor practical approach for controlling bidding with ever decreasing margins, will to all substantial test tunnel in the world” minute for political financial reasons.

Council are Jamal Rostami (Memberlast Nation industry canthe design, Spent fuel can also be reprocessed, with about 3% in current reactors,” he added. blasting vibration optimising advance in lead to “extinction” of contractors. works considerably safer. inThat Julythe2020.

With aim excavate of boosting assets was required.

Only rarely has the end of oneand project rolledwww.TunnelTalk.com 9 TunnelTalk AnnuAl Review 2014 Iran); Abidemi Agwor (Nigeria); Hamdi Aydin 2 a second capital updated guideline The WTC in Naples also hosted The 19m heading of the new Northern capacity of the underground station by The Option A SCL sprayed radial seamlessly tunnelling, onto a and subsequent Generation of nuclear power worldwide in 2017 as recorded by the World Nuclear Agency (Turkey); Choi Hangseok (Korea); Jeyatharan onThere the rebuild of machinery for mechanised more than 170 exhibitors representing 40%, the new structures include a new joint between the top heading and bench line running tunnel progressed as a fullare examples where Kumarasamy (Singapore); and investment.

Andres www.TunnelTalk.com TunnelTalk AnnUAl REviEW 2015 tunnel excavation. all sectors of the industry and from all face excavation on 1.2m advances.

It was Northern line platform and running tunnel to excavations eliminates the requirement this can happen, including in Singapore Marulanda (Colombia).

Mediterranean. The concept theThe floating ITACOSUF Committee convert the existing centre-island platform for the installation of reinforcement bars. a pilot heading for the platform tunnel and Hong ofKong where building out of on safety corners of the world.

At the 2019 General Assembly and session, tunnel for deepermetro watersystems crossings awaits in underground spaces, published a report All in all a busy, productive, significant to two separate platform tunnels.

The joint is formed fully using mechanised was enlarged to full platform cross section is an ongoing governmentMexico was elected as host of the WTC development of a prototype project along practice for design of cross- and progressive event. n on the current To complete the complex SCL (sprayed means, eliminating the need for the of 10.5m wide at spring line x 9.6m high. and ITA General Assembly in 2022 at the with the Trans-Atlantic hyperlink floating passages to support safety in rail and concrete lining) works, several technical resort of Cancun, gaining the majority vote References tunnel concept, which has been vision metroawww.TunnelTalk.com tunnels. achievements to improve constructability Fig 1. Plan (left) and 3D image of working site and access shaft • Steep curve ahead to keep ITA relevant – from competing host Member Nation India for several decades. and protect the workers were developed TunnelTalk, May 2016 and its proposed venue in Goa. Cancun, WTC experiences and implemented successfully. These high-speed worldwide: HighAs is the annual tradition at WTCs, there Mexico, might beMore expected to be arail more have included: rail, travelling at 200km/hr, is a to complain, and so for Video reporting were reasons popular choice, speed but India undoubtedly • Uphill and downhill excavation of 30 quick andfor more time and energy efficient Through 2019, TunnelTalk reported Naples it was the unseasonal rain and cold presents a greater need underground degree inclined escalator barrels in a from around the world, providing to travelling by air temperatures or by car for that ruined high expectations infrastructure asalternative the nation addresses coverage of major conferences top heading and combined bench/invert journeys of up to 500km. is of distance glorious Mediterranean sunshine as well urgent developments for city sewers, water That and projects, as well as sequence; greater with greater speeds on or shortage of baristas to serve as amaglev surprising supply lines, metros, hydro energy, intercity interviewing key industry players.

• Removal of load bearing foundation piles highways and hyperloop railways, systems. and irrigation impatient queues with Italian espresso; a View the TunnelTalk video reporting on the of four high-profile stakeholder buildings; YouTube channel: spread out of venueDouble of conference andtravelTunnelTalk networks. The WTC 2020 in Kuala Lumpur, More underground metros: A rule helix forrooms one way through the Sydney Opera House underground car park www.youtube.com/user/TunnelTalkVideos/videos areas that was demanding even Malaysia, has been severely disrupted by an exhibition thumb often quoted is that underground SCL advances through London Clay of the the coronavirus pandemic with most looking mass transit system is needed for fittest; cities and a wifi service, gratefully sponsored forward instead toofthemore 2021than WTC1tomillion convene population.

Givenby SWS Engineering, that in Copenhagen, Denmark in May 2021. that criteria, there is a lot to proved do, andunable that in its capacity to host all the as well as the app designed to help Additional business of the ITA at thethe users is before considering tremendous delegates navigate the technical sessions, 2109 General Assembly amountincluded: of work needed in cities of both sessions, meetings, and indoor, • Approval of three Nations more,new andMember less, than 1 million poster for sewerage outdoor and marquee exhibition areas.

– Kenya, Albania Lebanon. and and water supply in developing countries.

Nonetheless, SIG, the Italian Tunnelling • Approval ofTapthe the budget icecaps of andthe glaciers: Harvest and its organising committees, Association, which, for 2018, totalled anand Society 21 www.TunnelTalk.com TunnelTalk ANNUAL REVIEW 2020 the melting of iceflows glaciers and TunnelTalk reporting of the WTC event staged a WTC with a well constructed and annual income of more than €900,000 hold the fresh water in underground (above) and Salini keynote address (below) packed programme of technical paper with an expenditure of about reservoirs and €850,000 delivery systems, rather presentations and special social events. to create a surplus of about €50,000. than waste it into the sea.

At the Opening Ceremony, relayed • Approval of the proposal from Norway More hydro schemes: water video link between two theatres to to commission an external audit of theUsebyfresh for multi-purposes and help reduce organization, operation and governance accommodate the near 2,000 attendees, carbon emissions by increasing hydro Martin Herrenknecht delivered the Sir Alan of the Association as a one-off energy generation as the environmentally investment into its strategy for the future. Muir Wood Lecture, taking the audience responsible On another waterof TBM development through on a journey • Publication and release alternative. of the new relatedform theme, everyonehisbuy quality own personal career as a mechanical Emerald Book of have contract drinking water in bottles and turn current Fig 2. Design of a fully mechanised joint between top heading and bench fresh water networks into good quality, eliminating need of workers in the face Futuristic concept for high-speed trans-ocean travel but less expensive, grey water quality for TunnelTalk ANNUAL REVIEW 2019 www.TunnelTalk.com

A grim 2020 leads to a new world in 2021

GLOBAL PERSPECTIVE

East Asia and the Pacific region continue to be the drivers for global hydropower development, adding 9.2 GW of capacity in 2018. China accounted for the majority of that, adding 8.54 GW to pass 350 GW of installed capacity.

Leading the Chinese development is the 16,000 MW Baihetan project on the Jinsha River, which includes two underground caverns to house 16 x 1,000 MW generating units. Developed by the China Three Gorges Corp, the first group of units are expected to come online in 2021 followed by full commissioning by the end of 2022. Also under construction on the Jinsha River is the 10.2 MW Wudongde plant, which includes two underground powerhouses housing 6 x 850 MW turbines each.

Baihetan and Wudongde form the second phase of hydroelectric development on the Jinsha River, following phase one development of the Xiluodu and Xiangjiaba facilities. In total, the scheme will have a combined generating capacity of more than 46,000 MW. China is also investing in smaller-scale hydro and pumped storage projects as part of a nationwide shift to renewable generation and away from coal generating installations, long the dominant fuel for Chinese power generation.

Beyond China, development of the Greater Mekong region of Myanmar is advancing. The Myanmar Government has issued notices to proceed on both the 1,050 MW Shweli 3 project led by the French utility company EDF, and the 60 MW Deeoko project. Indonesia is also developing its hydropower resources with up to 6 GW under construction or in planning.

In Australia there are several pumped storage projects, notably the Snowy 2.0 project by Snowy Hydro and the Battery of the Nation initiative in Tasmania. Snowy 2.0 is expected to be complete by 2025

Jonathan Rowland, TunnelTalk plans. The Government of Honduras, for example, is planning several projects as part of a target to achieve 95% renewable energy in its power generating strategy by 2027. Throughout the region, projectsBrenner Baseline begins, face challenges from legal obstacles andAustria-Italy, 2010 security concerns. Cancellation of the 631 MW Diquís project in Costa Rica at the end of 2018 after objections from indigenous communities is a leading example.

MEGA PROJECTS

C

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East Asia and Pacific

to provide an additional 2,000 MW of capacity. Hydro Tasmania selected three sites in March 2019 to develop the Lake Cethana, Lake Rowallan and Tribute Power Station projects. Hydro Tasmania is now undertaking feasibility studies to determine the first site for development.

Hydro developments are being investigated in Papua New Guinea, the Solomon Islands, and on Fiji.

GLOBAL PERSPECTIVE

FOCUS: HYDROPOWER DEVELOPMENTS

ydropower developments added almost 22 GW of installed capacity worldwide in 2018, according to the International Hydropower Association (IHA).

Total capacity in 2018 stood at 1,292 GW with most activity taking place in the fastgrowing and emerging economies of East Asia and the Pacific (Fig 1).

Growth was also strong in North and South America with several major projects underway in Canada. Elsewhere in the world, pumped storage is a focus with major projects including the Snowy 2.0 installation in Australia and Ataqa in Egypt.

Expanding land-based transportation networks across the globe is driving the most marked increase in the demand for underground and tunnel engineering in history. Record sized mega-TBM drives, outstanding drill+blast excavations, and immersed tubes of extraordinary dimension are creating links between nations, across continents and under dividing straits at this beginning of a new era of global road and railway expansion.

Leading the way for European connectivity, and after 17 years in construction, was the Gotthard baseline rail link, completing all headings for the first of the twin tubes in 2010, for the second in 2011 and opening to traffic in 2016. This was followed by the Brenner baseline project with start of its exploratory bore in 2010 and all main line excavations currently progressing. Other main rail connection projects during the decade have been Hallandsås; Stuttgart 21; Mont Cenis on the Lyon-Turin baseline, the hard rock TBM and segmentally lined Follo Line, Norway; Koralm and Semmering rail lines in Austria; Crossrail and the HS2 high speed rail link in the UK; and the mega immersed tube Marmaray link under the Bosphorus; the combined road and rail Fehmarnbelt link; and plans for the rail link between Helsinki and Tallin. n

MEGA PROJECTS

H

T U N N E LTA L K A N N U A L R E V I E W 1 0 T H A N N I V E R S A R Y I S S U E

Global review of hydropower developments

Global connections

Brenner Baseline pushes ahead

Rail connections

GLOBAL PERSPECTIVE

Final TBM breakthrough, Gotthard baseline railway, Switzerland, March 2011

Credit: The Economist

Europe Lower reservoir of Snowy 2.0 pumped storage scheme

ea c o e dea M pec ca o TunnelTalk ANNUAL REVIEW 2020

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CASE STUDY: The need in India for the advantages of TBM excavation is immense. Not for the labour saving benefits, but for the speed and quality of construction. The introduction of large scale TBM projects in India however was the cause of much frustration. Resorting India’s appreciation and confidence in large scale TBM tunnelling was a tough assignment and one that Robbins accepted in full measure with its involvement in the AMR project in southeast India in the early 2000s.

Shani Wallis of TunnelTalk visited the project in 2008 to bring this case study report and visited more recently in 2023 to report on current status (p13).

TBM advantage applied to AMR irrigation project JANUARY 2009

“

We are here to make sure this happens,” said John McNally, Project Manager on the AMR job site for Robbins. “We have the first TBM now more than 1,900m into its drive from the downstream portal (by December 2008) and the twin TBM at the inlet portal is to start assembly in May.” McNally is speaking of the 44km (27 mile) x 10m (32.8ft) o.d. hard rock tunnel being excavated as the main element of an extensive network of tunnels and open canals that will feed irrigation and potable water by gravity to a vast drought-prone area of farmland and villages in the central State of Andhra Pradesh. The long tunnel, has been under study for several decades and passes from the upstream Srisailam reservoir on the Krishna River to the downstream balancing pond near Devarakonda on the Dindi River (Fig 1). The long straight tunnel under the maximum 500m cover is needed first to avoid any pumping in the gravity feed system, and secondly to protect the natural environment. The tunnel passes under the Nagarjuna Sagar Tiger Reserve, the largest sanctuary for endangered tigers in India.

The large contract of 1,925 crores INR, about US$400 million, is in the hands of Jaiprakash, one of the five largest construction companies in India, and includes several miles of open canal work as well as a second 7.25km long drill+blast tunnel on the alignment. Jaiprakash has extensive experience in drill+blast excavation, but little in the field of TBM tunnelling. When planning its approach for the long, large diameter tunnel, with no intermediate adits permitted, a TBM operation was self-selecting, but Jaiprakash needed more than a TBM supplier; it needed a partner to bring expertise and technological knowhow.

Extensive negotiations with Robbins culminated in the signing of one of the largest TBM supply orders to

Fig 1. Plan of the expansive AMR Alimineti Madhava Reddy irrigation and water supply network 3

In negotiating the contract, Robbins promoted the company’s OFTA – onsite first time assembly – strategy, which builds the machine in the launch bay at site and from components delivered from workshops and factories. The system was first used for the 14.4m diameter gripper machine on the Niagara water diversion tunnel in Ontario, Canada, and is proven to save weeks, if not months, on TBM delivery-to-launch-ready status. The considerable associated cost savings are shared by the contractor and the project owner.

Downstream jobsite and portal with OFTA assembly of the TBM

date. At a total of more than US$125 million, Robbins has three project contracts; one to supply two 10m diameter double-shield gripper TBMs, a continuous conveyor muck haulage system for both, plus spare parts and cutters from the USA and the other for supply of backup structures and other components from local Indian suppliers through Robbins India; and a third to supply, through Robbins India, a team of key personnel to manage the TBM boring process.

The landmark TBM order for the AMR project was signed in May 2006 and components for the first 10m machine began arriving in late 2007. In the meantime, Jaiprakash had excavated the 40m deep x 160m long TBM assembly and launch portal. The deep vertical walls of the drill+blast excavation, with hardly a rockbolt to be seen and no shotcrete at all over the protective mesh, foretold of the hard rock conditions to be met in the drive.

As with the Niagara TBM, OFTA of the first AMR TBM at the downstream outlet went “relatively smoothly”, according to Jaiprakash Project Manager, Anil Kamat.

“There were some minor mismatch problems,” he said, “but these were worked out”, and by March 2008, some 16 weeks after delivery of the first components, the TBM and its continuous conveyor system was ready for launch.

Ahead of this, production of the segmental lining in a set of moulds supplied by CBE of France had started and a sufficient stockpile of the six segments and key in each 1.6m wide ring was on hand. Robert Wagstaff of Lancing Precast Management in the UK was engaged as a consultant by Jaiprakash to advise on design of the concrete mix and set up of the casting yard. All excavated rock is being recycled into segment production. Each ring of 300mm thick segments, to an i.d. of 9.2m, is built in the tail skin of the double-shield machine, allowing ring build concurrent with excavation, the lateral grippers applying force against the tunnel walls to counteract the forward thrust of the cutterhead rams.

Assembled 10m diameter TBM with the Jaiprakash and Robbins teams The invert segment of the lining is installed directly against the rock in the partial tail shield and the others are lifted and placed using a vacuum segment erector.

More than this, Robbins committed itself to a stake in completing the TBM tunnel within the overall contract period. The 60-month construction period is penalty driven to be completed in 2011. “Signing such a big order and committing financially to the success of the drives is something we at Robbins felt was important, to establish confidence in TBM boring in India,” said Lok Home, President and owner of Robbins. “Our exposure to the penalty risk is mitigated by not taking responsibility for delay events beyond our control.”

Geology

Hard quartzite bands of up to 450MPa UCS, layered and separated by shale, is the predicted geology for about 50% of the long drive, with the remainder comprising granite of 160-190MPa. The need for a lining throughout the hard rock tunnel was explained by Bill Brundan, a Project Manager in India representing Robbins and advising Jaiprakash on the AMR project design.

“The contract required a permanent lining to meet hydraulic design specifications and to provide immediate support in reaches of potentially poor rock. Good quality rock cannot be guaranteed through the long drive particularly for about two thirds of the tunnel from the upstream portal where horizontal 4

The segment casting yard and stockpile at the TBM portal; the cutter workshop where worn and damaged cutters are reworked

blocky layers of quartzite and weak shales would have been difficult to support. Consideration was given to using an open gripper machine with a subsequent continuous concrete lining but this was rejected for logistical and programming reasons. A subsequent lining operation could not have been completed within the construction period and in reaches of low cover and in expected shear and fault zones, rockbolts and mesh would have been a time consuming support cycle. The prospect of needing large amounts of immediate shotcrete from off

the TBM backup also led Jaiprakash to adopt a one-pass segmental lining throughout with the 100mm annulus backfilled with pea gravel and subsequent grouting.”

To attack the hard rock, the 10m-diameter cutterhead is dressed with 67 front- or back-loading cutters with 20in rims on 19in hubs. The 20in discs provide for a longer wear life as well as application of higher cutter loads of up to 32 tonne/cutter. Specially designed drive motors allow the cutterhead to run at a higher than normal rotation to

Minor water leakage in the crown of the non-gasketed lining and long view of the 9.2m i.d. segmentally lined tunnel

5

compensate for anticipated low penetration rates. In the event of bad ground, the cutterhead is capable of vertical movement to allow overboring by up to 100mm outside the shield diameter.

Ground water inflows of varying quantities were predicted along the drive. Each TBM is fitted with a drill rig that can be used for probing as well as 360° pre-excavation grouting arrays. Weep holes through the segments will relieve buildup of water pressure behind the lining. The TBMs are also fitted with a more advanced real-time data logging system that monitors a greater number of TBM parameters, from hydraulic oil pressures and temperatures, to cutterhead motor amperage, cutterhead power, and gripper cylinder pressure - all vital parameters to monitor and control on these long 20km+ TBM drives.

Robbins goals

Following a grand celebration in March 2008, the first TBM began its long journey. The Robbins contract with Jaiprakash is based on achieving 400-500m/month for each TBM to have the 43.5km long TBM tunnel completed in a planned 50 months. The double-shield TBMs, their support systems, and the production schedule of three x 10hr overlapping shifts/day, six days/week for start of the first TBM, are all geared towards meeting this contract obligation. The continuous conveyor extends from a 500m cassette and travels at 3m/sec for a haulage rate of 800900 tonne/hr while the 12 VFD (variable frequency drive) motors provide a maximum recommended operating cutterhead thrust of 20,904kN. The vacuum segment erector supports a ring build cycle of about 30 minutes.

As well as up to 100 workers provided by Jaiprakash to each tunnelling shift, Robbins has a team of 53 directly employed staff – 13 experienced TBM expatriates and 40 Indian personnel including office staff, managers and shop mechanics. “The learning curve has been steep,” said McNally. “This is a big machine to manage and its continuous conveyor, vacuum segment erector and segment delivery systems have taken time to master.” In addition, crews have had to battle conditions beyond their control. One of the most critical is supply of electricity.

The TBM is powered from the 33kV national electricity grid and transformed on the TBM backup to run the machine’s 22kV/690V/400V electrical systems.

Unfortunately, reliability of supply has been a major problem through the first nine months of the drive.

Electricity blackouts and drops in voltage have caused

regular trips and abrupt shutdowns of the TBM. “At worst we have had 45 power cuts in a week and as many as 15 in a single day,” said McNally. There is a diesel generator station on the site but this is not used for long-term power supply. It is fired up in emergencies and to compensate for power cuts. When the grid is restored the expensive diesel generators are shut down.

As well as causing potential damage to the TBM systems, the cuts play havoc with the operating routine. Not only do they shut down the TBM without warning, the continuous conveyor, powered also by electrical VFD motors, stops in its tracks. TunnelTalk experienced one of these power cuts while visiting the TBM. The machine had just started its next stroke and the cutterhead was reaching optimum rotation when a power cut plunged everyone and everything into silent darkness. Restoration of the lights and power was achieved in about 5 minutes when the diesel generators kicked in.

The seriousness of the unreliable electricity supply is emphasized when remembered that the TBM is only at the start of perhaps a further 25km or more before it junctions with the TBM from the other end. When the issue was raised with the senior Jaiprakash manager on site, the response was that power cuts only last about five minutes until the emergency generators come online. This ignored the adverse affects of the cuts on the entire operation. Even through the learning curve, “training the workers to operate the machine requires consistency,” said McNally, “and we haven’t had that on several scores. In addition to frequent power cuts, we have had to deal with adverse geological conditions and large water inflows.”

Boring conditions

While the large open cut at the portal illustrates the strong quality of the rock, it also forewarned of blocky conditions.

The rock is blockier than anticipated and this did start causing immediate problems on the conveyors. The 20in cutters were said to be withstanding the conditions well with cutter use reportedly less than predicted, and extra grizzly bars across the cutterhead openings have helped reduce damage on the conveyors.

Water ingress of up to 700lt/min through the face has also caused difficult conditions. When TunnelTalk was on the TBM, a ring build was in progress. At that time, the drive was in a particularly wet reach with water coming in through the cutterhead and gripper shield and over the ring build area. It was said that water ingress does not

Blocky rock plays havoc on the continuous and stacking conveyors causing frequent tears and rips; Water ingress running on the continuous conveyor and pouring over the segments in the invert of the ring build area

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Fig 2. Week 40 progress and TBM availability statistics

impair the effectiveness and safe operation of the vacuum segment erector, but it was retarding the ring-build. Water was streaming across the segments in the invert pick-up zone and flowing through and around the tail shield as workers bolted up the joints. Then the lights went out.

Fortunately, the fail-safe system on the vacuum segment erector is not directly affected by the power cuts but the safety hazard of the black outs was clearly evident.

The greatest impact of blocky rock and water ingress was on the conveyor system. From the face, the conveyor comprises four flights. The TBM conveyor discharges onto a transfer belt that crosses the backup and loads, via a hopper, the continuous conveyor. At the portal, stacking conveyors discharge onto stockpiles.

Excessive water loading onto the belts creates major problems, particularly on the TBM cross conveyor and into the hopper to the main conveyor. The cross conveyor is enclosed in a box cover but water travelling up and onto the start of the continuous conveyor is making working conditions tough. On the long continuous conveyor, the sharp edges of the granite blocks have caused serious tears, the most extensive, caused by a piece of rock jammed at a roller point, tore the belt in half length wise.

A full 1km length of belt had to be replaced. At the far end, it is the blocky nature of the rock that causes the trouble.

“The heavy blocks bounce over the rollers and were rolling backwards down the inclined stacking conveyor,” explained McNally. Modifying this to a more gentle incline and creating a closed loading chute helped a more smooth transfer from the continuous belt.

Advance to date

Despite the interruptions and delaying factors, the TBM had progressed a total 1,874.42m or 1,162 rings from launch in March to end December 2008. “When the TBM and all the support systems are running sweetly, we have recorded advance rates of up to 103m/week. Our best day to date is 23.11m,” said McNally.

Also, although average availability of the system is disappointingly low, due largely to circumstances outside the control of the tunnel operating team, there have been

good weeks. The weekly boring report for Week 40 for example shows a TBM utilisation of 41% and a 89.24m advance in the week’s 55.7h boring time (Fig 2).

While the power cuts are a major safety and operating hazard, they accounted for 3% of total unavailability for Week 40 and amount to between 2% and 4% on average. “Avoiding the power cuts would not add significantly to the overall advance rate,” said McNally, “but they really should not be part of the equation. They are a major interruption and have certainly extended the learning curve.” Eliminating these cuts over the long term and through the coming years of operation by the two TBMs was said to be an issue being addressed at project director level. Conveyor downtime in Week 40 accounted for 1% of availability downtime and cutter changes for 14% (Fig 2).

Since start of the drive, statistics show a positive trend, progressing per month through the learning curve from 40m to 100m, 220m, 280m, 300m and up to 360m for the month of November. “This is still low and we are well behind the average needed,” said McNally, “and it didn’t help that we launched into a very hard dyke intrusion, but the machine, its support systems and, with time, the team will be able to achieve better once we get into a consistent, uninterrupted routine. Through the coming months we need to be achieving much higher monthly rates to reach the 450m/month as an average.”

At the other end of the long tunnel, Jaiprakash was busy with a major earth moving exercise on the left bank of the Srisailam reservoir to create the cofferdam and assembly bay and operating site for the contract’s second TBM. From the main outlet site and its segment casting yard, it is a 1.5hr journey to the inlet portal. Some parts of the second TBM are at the main portal site while other components are being delivered directly to the upstream site. “Making sure these components are unloaded and stored and protected properly is a concern,” said McNally.

“We are hoping to take delivery of the portal site to start building the machine by early May next year and the second machine is now programmed for launch on its downhill heading in about August next year (2009).”

7

Downstream portal after launch of the TBM (left) and earthworks to create the upstream TBM assembly bay and portal

Contract partnering

By entering into agreements that involve greater responsibility for the outcome of the contract, Robbins is taking on considerable risk, but as Lok Home explained, “this is something that is increasingly being asked of machine manufacturers, especially in developing countries where the need is great and the domestic experience of TBM tunnelling limited. On-site-first-timeassembly of TBMs, especially for large machines, will become an industry-wide standard to take advantage of the significant time saving benefits,” and taking more responsibility for actual performance of the machines will be needed, particularly in the short term, “if application of TBMs in developing countries is to be progressive and the start of a domestic base of knowledge and experience”.

Unfortunately, early joint ventures with international construction companies has not been a positive experience in India, with international partners supplying used machines that were not up to the task and abandoning the engagement when all goes horribly wrong, as happened at Parbati where the used machine has been stranded in the flooded heading for more than a year. “This experience has to be reversed and if that means us partnering with the Indian main contractor to manage the TBM operation, that is a process we at Robbins are willing to negotiate and take on,” said Home. “We have entered various types of co-operative agreements beyond the standard TBM supply and cutter consumption contracts. These range from guaranteeing TBM availability to assuring negotiated progress rates as here at AMR. At the Olmos project in Peru, we are responsible for ensuring 85% availability and a minimum 2.5m/hr penetration for the 5.5m diameter gripper TBM in the 13km long headrace. Of course there is the risk of falling below the guarantees and assurances, and here at AMR, in the early days, we are not yet meeting the required progress rates, but in Peru we are getting 90%+ availability and up to 4m/hr penetration – a very good result.”

McNally came to the India as Project Manager for Robbins at AMR from the Peru project and is finding that there is a significant cultural difference between partnering in the two countries. “Here at AMR we are being considered more as a subcontractor than a partner but Jaiprakash is becoming more involved in the dayto-day operation of the tunnelling process. The overall contract does involve other major works but the tunnel is far the largest part of the total $400 million value and 8

Robbins is managing the TBM process according to a long schedule of agreements.” TunnelTalk was shown the large folder that holds the printed copy of the agreement that itemizes right down to supply of tools. “There have been some issues in translation and interpretation of the agreements,” said McNally. “For example, does supply of ‘hand tools’ include supply of ‘powered hand tools’ such as power wrenches used for bolting up the segmental lining? Also, commitment to supply local workers to the tunnel and site management tasks at the portal has fallen short in that workers with some experience are needed.

To fill the experience gap we have had to employ more than the quota agreed in the schedule.”

The main contractor is also responsible for a reliable power supply. “If we had been responsibly for power supply we would have priced to run the diesel generators full time to generate our own uninterrupted supply,” said McNally. On this point, all contractors working on current contracts for the Delhi Metro and its express airport rail link tunnels are generating their own electricity. This is not only preferred by the contractors, it is a contract requirement of the client, knowing that national grid supply in the city is overstretched and unreliable.

However, all new contracts are a new experience and with commitment, Robbins will see the long AMR tunnel through. In the meantime, the company has entered into similar supply and operation agreements for two further TBMs for major irrigation projects. The first is for the Pula Subbaiah Veligonda project on the left bank of the Srisailam reservoir where the new double-shield machine will excavate a 19.2km long tunnel to deliver water to the Prakasam, Nellore, and Kadapa districts of Andhra Pradesh. The machine has just started OFTA assembly for the HCC-Coastal JV, for a projected launch in early 2009, and will advance a parallel drive to a 7.7m diameter Herrenknecht machine that is in the start-up phase of the parallel 19.2km drive for the NSL-SEWSabir-Coastal JV. The second new Robbins machine, also 10m in diameter, is an EPBM for the Slemmanabad carrier canal tunnel on the Bargi Diversion Project in Madhya Pradesh State near Juabulpur, about 800km northwest of the Srisailam projects.. There Coastal has the contract to drive the 12km long x 9.2m i.d. segmentally lined tunnel within a 40-month contract period.

TunnelTalk Reference •

Niagara plan of attack – Dec 2006

TBMs assembled and ready for parallel drives at Veligonda and Sleemanabad

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y late May 2009 the 10m diameter Robbins double shield TBM to work on the 19.2km long tunnel No 2 drive of the Pula Subbaiah Veligonda project for the Coastal/Hindustan Construction Company JV was fully assembled and ready for launch.

The reservoir intake will be located approximately 60m parallel to the 7.9m diameter tunnel No 1, which is currently being excavated by a machine supplied by Herrenknecht.

The smaller 7.9m diameter Herrenknecht double shield TBM achieved an advance rate of 525m in a single month, which came as a welcome boost for a drive that reached standstill for more than a year after the machine became stuck following inundation under high water pressure.

Using the OFTA onsite-first-time-assembly process, the Robbins 10m diameter double-shield TBM for the project was assembled in approximately four months. “The real savings in using OFTA are time-related,” said Jim Clark, the Robbins Field Service Project Manager. “The lead time between the TBM order and components arriving onsite is much shorter and the machine does not have to be assembled and disassembled at a shop prior to shipping.”

Robbins is providing a formal training program for contractor personnel, covering all aspects of TBM operation and maintenance prior to the launch.

Both the AMR and Veligonda projects draw water from the Srisailam Reservoir and are part of the extensive scheme to provide ample irrigation and drinking water in the drought-prone region.

Utilizing back-loading 20in cutters, the Robbins Veligonda machine will excavate a mix of quartzite, shale, and

phyllite from 90 to 225 MPa in UCS. As the TBM bores, it will erect a 300mm thick segmental lining comprising six segments and a key in each 9.2m i.d. ring. For muck haulage, Robbins has provided a continuous steel cable conveyor belt. As one of the most extensive conveyor systems ever used in India, it will extend 19.2km and will require four main drives and three booster drives.

In mid-2009, all TBM tunnels on the AMR and Veligonda projects were scheduled to go into service in 2014.

Hybrid EPBM for Sleemanabad

The 10m Robbins hybrid EPBM ordered for the Patel/ SEW/Coastal JV has launched on a drive of wide-ranging geology and will face conditions that range from hard, massive marble to soft running gouge on its 12km long Sleemanabad water transfer tunnel.

The TBM is a fully functional hard rock single shield machine and a soft ground EPBM built to bore in long sections of 180 MPa UCS jointed rock and marble, interspersed with clay and gravel. In sections of soft ground, the TBM runs as a standard, pressurized EPB system with an abrasionresistant, shaft-type screw conveyor. When sections of rock or mixed conditions are encountered, the machine can run in non-pressurized open mode. In longer sections of rock, the machine will convert to a hard rock single shield setup with the screw conveyor removed and replaced with a TBM belt conveyor.

The machine began excavation in full EPB mode, as the first 3km of the 12km long drive is expected to consist of mainly soft ground. After that, the machine will be

OFTA assembly of the 10m Robbins hybrid EPBM for the Sleemanabad project

Time lapse video of the assembly 9

operated as a non-pressurized EPBM or as a hard rock single shield depending on ground conditions.

Ole Pederson, the Robbins India Jobsite Manager, cited the remote project location and transport of parts as challenging aspects of the assembly and launch. “Local support is easing these difficulties while providing an economic boost to the area,” said Pederson.

The Sleemanabad carrier canal is part of the Bargi diversion project for the Narmada Valley Development Authority, a division of the Madhya Pradesh State Government. The major trans-valley canal will stretch 194km from the existing Bargi Dam on the Narmada River and transfer 152m3 of water/sec to the Katni, Satna, Panna, and Jabalpur districts, irrigating more than 100,000 hectares of land.

Rescue missions and progress to date

A

ll five TBMs on the long irrigation and water supply tunnels – two Robbins 10m double shields on the AMR project, a 10m Robbins double shield and a 7.8m Herrenknecht double shield on Veligonda, and a 10m Robbins double shield at Sleemanabad – have all struggled with serious problems. These have ranged from contractual, funding and progress logistics issues to extreme geological conditions to mechanical problems and breakdowns.

Contractual problems have invariably risen out of geological and mechanical difficulties that have seriously delayed anticipated progress. Funding issues have then followed on when progress rates fell below expectations and mechanical and geological conditions have held up any progress. The stalemate of a TBM stuck in bad geological conditions or stopped due to mechanical issues, together with strained contractual relations between client, contractor, machine supplier, and compounded by lack of money to prepare a recovery strategy held up progress by the machines and their entire support systems and crews for months and years. All three TBM projects are years behind schedule, some of them delayed currently by 10-15 years, and all have gone well over the original projects estimates and budgets.

Serious flood setback

An early devastating setback on the AMR project occurred during assembly of the upstream TBM in October 2009.

Assembly was complete and launch was just days away when disaster struck and an overtopping of the cofferdam completely flooded the inlet portal working site. Exceptionally heavy rainstorms charged the levels in the chain of Srisailam Reservoirs leading to rises in water levels by up to 3m in a short period of time.

The unprecedented rainfall called for emergency management of the water levels in the reservoirs.

Opening release gates to control levels in an upstream dam contributed to extra charging of the downstream reservoir and overtopping of the tunnel site cofferdam submerging the TBM and all to be seen to the top of the site’s gantry cranes.

There was a flood at the outlet working site as well but with less serious consequences. The site was covered in thick red silty mud when the water subsided and access to the job site was cut off for a few days as a swollen river on the access road made it impassable.

After pumping out the flood water back into the reservoir, recovery of the upstream portal site required total rebuild of the wrecked TBM. But, as is the motto of the international tunnelling industry, no project started never gets finished. All projects started get finished and so it will be with these three projects.

The vital need for the projects has not gone away and has become more acute over time. As well as bringing fresh drinking water and agricultural irrigation water to vast areas of the drought prone region of India, there are two further significant needs. One is to dilute the high level of natural fluoride in the ground water that currently supplies most of the drinking water and irrigation water to these areas. The levels are dangerously high for animals and humans and there is no cure for the debilitating bone fluorosis disease.

The other issue of the long-term delay of the project is that all these projects are based on capturing the surplus water of the monsoon season and on gravity feed of the water for hundreds of kilometres. At present, the surplus monsoon rains overtop the spillways of the dams and flow to the sea. This resource is to be captured. The importance of gravity feed of the new systems is to eliminate pumping systems that take downstream flow of the rivers and pump it back up to the higher ground for water supply and irrigation needs. These massive pumping systems operate constantly and are expensive to operate and maintain. The savings to State budgets by eliminating or reducing the need for these pumping systems would be tremendous, especially when funding is needed from

When flood waters overtopped the AMR upstream site cofferdam, recovery after pumping out the water required total rebuild of the submerged the TBM

10

the public purse for so much else. So the projects must get finished. Much of the associated weirs and dams, networks of canals and drill+blast excavation of shorter tunnels have been built and all is waiting for the holethrough of the long TBM drives.

A report on the current status and intervening issues on the AMR project, following a return visit in January 2023 since the first site visit and report in 2008, is published by TunnelTalk recently – and the news is good. After the long delays, there is a way forward technically, contractually and with committed Telangana State funding to complete the remaining 9km of hard rock boring on the long 44km excavation project that separates the two TBMs from their in-tunnel junction.

At Veligonda, the parallel tunnels were awarded in 2008 - Tunnel 1 with the Herrenknecht TBM to the Sabir/ Sew & Prasad JV, which sublet the tunnel works to the Nuziveedu/Swathi/Coastal JV, and Tunnel 2 with the Robbins TBM to the HCC-Coastal JV. The Herrenknecht machine started first and progress through the hard quartzite, slate and phyllite rocks proved slow. The tunnel is lined with a hexagonal type segmental lining with four segments in each offset ring. This is said to be one of the largest tunnel diameters lined with this kind of lining. As it progressed the TBM encountered several faults and in 2012 the machine became stuck in a fault zone of mud and high-volume, high-pressure water inundation. After standing still for a year, a team from SELI of Italy assisted in freeing the trapped TBM and creating a cavern around the machine to assist in its necessary repair and refurbishment.

The Veligonda project was started by the late former Chief Minister YS Rajasekhara Reddy of Andhra Pradesh State. A change of State Government legislature in 2014, when the large State of Andhra Pradesh was split into two with the formation of the new Telangana State, caused a hiatus for both the Veligonda project that remained in

7.8m diameter Herrenknecht double drive assembled for its drive at Veligonda

10m diameter Robbins TBM assembled and ready for launch at Veligonda

the Andhra Pradesh jurisdiction, and the AMR project that became part of the new Telangana State. While 11.5km of the first Veligonda tunnel and 8.7km of the second were completed during the tenure of Rajesekhara Reddy, only 4.33km and 2.35km of advance in each tunnel was achieved in the years 2014 to 2019 when elections brought in another change of State Government, back to the administration that had started to project. The late Reddy’s son, YS Jagan Mohan Reddy, now as Chief Minister, claimed that the Government completely neglected the projects in the intervening years and secured renewed support and funding to have it finished without further delay.

For Tunnel 1, after poor performance, the contract was terminated in 2019 and relet to Megha Engineering and Infrastructure to complete the last 3.6km of the 18km long drive. Under the new contractor and after 12 long years, the Herrenknecht TBM completed the last 3.6km of its long drive and broke through in January 2021.

Work on the parallel 18.8km long tunnel by the larger Robbins TBM had also become trapped for several months in geological fault zone in 2012 and it too had been freed with the assistance of the SELI team. Following take over of the project by Megha Engineering, the TBM is currently stopped with contractual and financial issues yet to finalise. The Chief Minister however had promised in February 2023 that the last 4km will be completed by the end of the year.

At Sleemanabad in the neighbouring State of Madhya Pradesh, the 10m diameter Robbins EPBM has suffered similar contractual, technical, and geological problems. In 2012, the same SELI team assisted in freeing the machine when it had become trapped.

The TBM is progressing currently and with about 6km completed and another 12.8km to go there is no forecast for the completion of the project, but completed it will be. n 11

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Reserves and usage of fresh rainfall water in India is critical in many parts of south India for both irrigation and human and animal consumption

AMR project in India

on a path to greater success

AUGUST 2023

T

Shani Wallis, TunnelTalk

wo 10m diameter double shield TBMs are in the final stretch of an epic 15-year excavation on the AMR project in India. Less than 9km remain of the 44km long segmentally lined water transfer tunnel.

Many circumstances over the years have conspired to compromise progress - not least lack of funds, the Covid hiatus, and major political changes. With only 9km - only 9km - separating the two machines from their in-tunnel junction, there is renewed commitment to get the job done.

Indian construction company, Jaiprakash Associates Ltd of the Jaypee Group, received the contract for the long water transfer project in 2005 for INR 1,925 crore, about US$400 million. India’s industry policy is to award contracts to the L1 lowest bidder and after negotiations, Jaiprakash was engaged. A group from China had submitted a lower bid that was technically incomplete and had left the project as soon as the scale of the undertaking on-site was realised.

Jaiprakash had extensive experience in heavy civil construction, including a major project in Iraq in 1984, where it completed about 2,000km of sewer and drainage networks and pumping stations for the city of Baghdad. It also had limited experience in large-scale TBM mechanised tunnelling based on taking over the Dul Hasti hydropower project from the original French contractors that had deployed a Robbins TBM for the headrace. With more drill+blast experience, the decision on Dul Hasti was to abandon the TBM excavation, driving it off-line out of the way, and to complete the drive with drill+blast.

Before bidding the AMR project, Jaiprakash entered an agreement with Robbins to not only supply the two TBMs and their complete support systems, but also for a TBM service, maintenance, and operations contract for the duration of the project. On being awarded the AMR contract, Jaiprakash attempted to subcontract management of the tunnelling work to a Chinese subcontractor, but Robbins was not able to take on the risk of negotiating and working with a subcontractor, and when the Chinese pulled out of the discussions, it was back to a Jaiprakash-Robbins partnership for this long tunnel undertaking.

The agreement with Robbins was based on a projected progress rate of 500m/month/machine to have the 44km hard rock, segmentally lined excavation completed by two machines and handed over in about four years, in 2012. Exposure of the risk taken on by Robbins excluded any stoppages outside the control of the Robbins team.

Fig 1. The AMR project is designed to deliver annual monsoon surplus water from the Srisailam reservoir to a drought-prone and fluoride-contaminated groundwater in the Nalgonda district of Telangana State

Components for the two Robbins TBMs arrived on site in late 2007 and early 2009, respectively. Both were assembled using the Robbins OFTA onsite-first timeassembly process, and the first machine launched on its slight uphill drive from the downstream portal in May 2008. The second TBM would progress on the down gradient from the upstream portal near the Srisailam reservoir on the Krishna River (Fig 1).

Project stipulations

The prime purpose of the Srisailam reservoir is to generate hydroelectricity. Little can be spared for draw-off for other purposes. As a result, after passing through the generators, water is captured downstream and pumped back up to the high ground for drinking and irrigation to the vast drought-prone area of southeast India to the northwest of Hyderabad. The concept of the AMR project 13

Upstream inlet portal

Downstream outlet portal

Two 10m diameter double shield rock TBMs are excavating the 44km long segmentally lined tunnel from the inlet and outlet portals only making it one of the longest such excavation projects ever undertaken

is to capture the seasonal monsoon surplus into the Srisailam reservoir, which would otherwise flow over the dam’s spillway and away to the sea, and instead, deliver the water by gravity on a long journey of tunnels and canals to feed into local irrigation and fresh drinking water supply networks (Fig 1). Gravity feed of the surplus water into the reservoir will reduce substantially, or eliminate, the downstream pumping systems. These are expensive to run and maintain. The gravity feed system will save as much as US$50 million/year in pumping costs alone.

The expansive project is also urgently needed to dilute or replace groundwater consumption in the area. The groundwater is highly contaminated with natural fluoride, which causes fluorosis bone disease in animals and

humans for which there is no cure. Despite the delays, the need for the AMR tunnel project remains urgent.

A TunnelTalk site visit and subsequent article in 2008 detailed the mobilisation of the two construction sites and the experience of the start of the two TBMs and their support systems. The current report is compiled after a return visit to the project in 2023 to know of the current status and the events of the intervening years.

By early 2023, the downstream portal TBM was 20.4km into its drive, and the upstream TBM was 14km into its heading. Of the 44km to be excavated, just 9.6km separates them. The downstream TBM was advancing when TunnelTalk made its visit, inching its way forward with a badly damaged main bearing until the bearing would go no further. The upstream portal TBM has been stopped since December 2019. It had been running well on its down gradient heading but was stopped in its tracks when it hit a fault zone of mud and gravel carried into the excavation chamber by high-volume, high pressure water ingress, clogging completely the cutterhead.

Undertaking of epic dimensions

The two TBM headings divide equally into two long drives through two principal rock types – the downstream heading for 22.5km through hard granite and the upstream drive through 21km of hard abrasive quartzite with an anticipated 200m of conglomerate of unknown quality between the two. The alignment runs directly beneath a national sanctuary for endangered tigers and other protected wildlife. A condition for approval of the project was that there would be no construction activity of any kind at all in the confines of the sanctuary.

Samples of the hard granite of the inlet drive (top) and the hard abrasive quartzite of the outlet drive (below) are separated by an anticipated 200m of conglomerate of unknown quality 14

This results in: • one of the longest tunnels in the world portal to portal; • one of the longest, large diameter tunnels excavated from only the two portals; and • two of the longest, large diameter, segmentally lined, hard rock TBM headings ever.

Service trains carry crews, segments and supplies to each TBM and long continuous conveyor systems haul the muck from each machine on its long heading

There can be no denying the tremendous scale of the undertaking in excavation terms. Additionally, there could be no core drilling geological investigations within the tiger sanctuary. There were, therefore, no full-alignment pre-tender cores to inspect and no geological data about rock conditions or water ingress expectations other than desk studies and surface observations.

The challenges of operating two large TBMs in India were based on limited previous experience and largely on two hydropower projects in the Himalayas in the 1980s.

After taking over at Dul Hasti, Jaiprakash abandoned the TBM drive and completed the headrace with drill+blast for hydro generation to come online in 2007. At Parbati II, two machines had different fortunes. The machine on a short steep penstock had problems but pushed through. The machine on the long headrace drive has battled through extremes of geology from the start and has suffered mechanical problems and bearing failures.

Now, nine years after starting in 2014, it is about 300m from its finish, but as of early 2023, both the TBM and its opposite downhill drill+blast heading are again stuck and dealing with extreme rock bursting and highvolume water ingress, conditions indicative of the young Himalayan geology. Power generation is again delayed from a previously achievable start in 2023.

Along with these TBM projects and the two machines at AMR, another four TBMs were procured for two additional long irrigation projects also in southeast India. A 10m o.d. Robbins TBM and a 7.8m o.d. Herrenknecht TBM were procured for the 18km long parallel tunnels of the Veligonda project, and there is a 10m o.d. EPB Robbins machine with rock boring capabilities and a 10m o.d.

Herrenknecht EPBM working from the other end of the 12km long tunnel for the Sleemanabad project. All have faced problems, from delayed funding to termination of a contract, from geological extremes to mechanical failures and logistical setbacks. One of the four machines, the Velagonda Herrenknecht TBM completed its drive in January 2021, after starting in October 2008, passing

through a contract termination and rebid, and being rescued from being stuck for more than a year. The other three continue and are within sight of their breakthroughs in the coming months.

Three other projects have since proven the ability of modern TBMs in the geological conditions of the Himalayan foothills. In April 2019, a 5.06m o.d. Robbins double shield completed the 12km x 4.2m i.d. segmentally lined Bhari Bhabai water supply tunnel in Nepal and in record-breaking time achieving more than 1,000m in a single month. The same TBM with an upsized cutterhead to 6.4m diameter is currently being used by the same Chinese contractor, COVEC, on the 13.3km segmentally lined Sunkoshi Marin diversion tunnel project also in Nepal, which is currently more than 6km into the drive and running months ahead of schedule. Before these projects, in the early 2010s, a Seli-shielded TBM made good progress on its 14km drive for the Kishanganga hydro project in Kashmir, with drill+blast advancing from the opposite portal. The fortunes of these TBMs are recorded in reports in the TunnelTalk Archive.

At AMR, while there was great optimism initially, reality set in with early setbacks and difficulties. From the downstream portal, frequent national grid power outages caused sudden shutdown of the machine and its continuous muck-hauling conveyor and other support systems. Hard rock at 250MPa strength and peaking at up to 350MPa, caused high mechanical stress on the TBM, and a new bearing was needed at 10.6km after 7,040 bearing hours into the drive. This was the second new bearing for the pair of TBMs. The upstream TBM needed a new bearing during machine assembly when unprecedented 1:1,000 year monsoon flood water into the Srisailam reservoir days before launch overtopped the jobsite cofferdam flooding the site and its TBM. Recovery of the machine was a complete rebuild.

Needless to say, once into their drives, the guarantee of 500m/month/machine was nowhere in sight. Additional 15

factors, aside from the TBMs, the geology, or the tunnelling process, kept advance in the low 10s of meters/month.

A serious contributor to slow progress is that it is hard to bring a project back on track once delay sets in. It is also difficult to reshape the premise of the contract and the thinking of the client. If contract payments are based on meters advanced, convincing the client that it must pay for stoppages to free a trapped TBM or repair mechanical issues is practically impossible. The client’s position is that it is paying for progress and a finished project. Fixing geological and mechanical problems is the contractor’s cost.

A political shift in ownership of the project then caused significant interruption. In 2014, the State of Andhra Pradesh, the original owner of the project, was split, and the project came under the jurisdiction of the new State of Telangana. Political championship of the project almost vanished while the administration of the new State took shape.

But staying for the long haul has been the commitment of Jaiprakash and Robbins. According to Glen Maynard of Robbins and current Manager of Operations for Robbins at AMR, “there is now new impetus to rally to the cause, get the two TBMs working again and move on to better things.”

At the upstream heading, having run into the fault zone in December 2019, the decision was made to investigate the rock ahead using the Swiss Amberg TSP Tunnel Seismic Prediction system.

The fault zone that stopped the machine in December 2019 was encountered about 600m after a major inflow of water at up to 10,000 litre/min in October 2018. That situation required an extended programme of forward grouting, including chemical grouting. Running parallel and near the Srisailam reservoir, the fear was that these fault features were connected directly to the reservoir Model of a pre-excavation grouting plan that might produce only marginal results

water source and that the machine was now at the start of a long length of bad conditions. Since stopping in December 2019, water ingress through the face has continued at a steady 1,500 litre/min with no fines carried in as the water flows constantly through the course gravel that has clogged the cutterhead since meeting the fault zone. “Another cycle of grouting was a possibility, but grouting is an unquantifiable process on time, materials, and money,” said Maynard. “We had tried probing ahead to know what we were dealing with, but that wasn’t giving us what we needed. We needed to ‘see’ inside the rock, which is what seismic prediction provides us.”

The Amberg TSP Tunnel Seismic Prediction method of Switzerland had been used earlier on the Parbati project.

Being an unlined heading, the results of the process for that application could be verified as the TBM resumed excavation to reveal an accurate correlation between the TSP prediction and conditions as met. At AMR, approval for seismic exploration was granted in December 2019, and the Indian agent of the Amberg TSP system was engaged to undertake the investigation. After a week on site, the report arrived four weeks later in January 2020 to predict the fault as about 3m wide with good quality rock continuing on the other side (Figs 2, 3, 4).

Unfortunately, at that moment, the Covid pandemic brought all work on the project to a stop. It is only since September 2022, that work has slowly resumed and with a skeleton crew at the upstream site to oversee the stuck TBM. During the Covid downtime, the electricity provider unfortunately stopped providing electricity to the upstream site in early 2020 due to unpaid electricity bills.

In the down-grade heading, this had the inexorable result of slowly flooding the heading. Water in the 14km x 1:3,200 down-gradient heading flooded the TBM to about its axis, extended well back toward the portal, and submerged the continuous conveyor for about 4,000m of its length.

In August 2021, after a hiatus of two years, the Cabinet of the Telangana State Government made a renewed funding commitment to complete the project. From the early ownership of the project by Telangana State in 2014, its funding was a concern. Under previous ownership by the Andhra Pradesh State Government, the project should have been already completed, in operation, and saving the new State Government water pumping costs since 2012, but in 2014, the project was still far from being complete, and its ongoing costs for standing still were proving expensive.

Several alternative funding models were explored, including private funding and public-private partnerships.

But these had particular issues, as Anil Kamet, B E Civil President for Jaiprakash in Hyderabad, explained in a meeting in 2023. “The problem is that the value of the project is the monsoon surplus into the reservoir. If the monsoon fails, then the surplus is not there. For any private investor, the source of revenue is not assured.”

The project had to remain publicly funded.

In its renewed commitment, the Telangana State Cabinet directed that power supply to the upstream heading be restored with the Government taking over the electricity supply payments and paying the back amounts due.

This began the two and half months of 24/7 pumping to recover the flooded heading.

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Set up and results of the TSP, Tunnel Seismic Prediction, system

Fig 2. Set up for completing a cycle of seismic wave velocity readings into the rock ahead of the face

Figs 3 and 4. After processing the recorded data the results are illustrated graphically with the blue colour representing harder rock and the red weaker conditions 17

A pumping capacity of 7,000 litre/min was established to overtake and drawdown the consistent 1,500 litre/ min of water flowing from the face through the clogged cutterhead and the litres/min accumulating at the front of the downhill heading. Along the 14km drive, the pumping system comprises five pumping stations – one every 2.5km, plus another at the portal - with five 100hp pumps/station serving five pipelines, including reversal of the two lines that would normally be bringing cooling water to the heading.

During the 2023 visit, an early morning journey took us from base camp at the downstream portal, up to the upstream jobsite, across the Tiger Sanctuary (seeing wildlife, including peacocks and monkeys, but sadly no tigers), and into the 14km long heading.

With no excavation activity, the site offices, workshops, accommodation camp (that had been hosting up to 25 or more construction engineers), segment casting yard, and workshops were all quiet and had a feeling of being abandoned. In the heading, each of the in-tunnel pumping stations was manned and monitored around the clock, and the 7,000 litre/min operating capacity was keeping the constant water ingress at bay. The pumping station at the portal was on constant duty to pump the water out of the cofferdam-protected site back into the reservoir. Given the overtopping of the cofferdam during TBM assembly in 2009, the height of the cofferdam had been raised by 3m and is now above the high-water spillway level of the Srisailam dam. No chance of any further flooding of the jobsite was the assurance of Deepak Jain, the Project Manager on site for Jaiprakash.

After an hour-long man-rider journey, we arrived at the TBM. Walking up onto the backup was like climbing onto a pumped-out sunken ship. Everything was rusted and

ruined. The steel superstructure was covered in wet red rust, all the electrical cabling had perished, the exposed wire strengthening fabric of hydraulic hoses was rusted, the operator’s cabin and crew cabins were mouldy and dripping wet, and up front at the TBM face in the dim humid light, clear water was running unchecked through the blocked and rusting cutterhead and around the motors, gripper shield, segment erector, and ring build area. Looking at the scale of the job at hand, it was difficult to see where work would begin to get the TBM and its systems back up and running to resume excavation.

A start had been made to rehabilitate the crew’s rest cabin with old plywood cladding stripped out and new cladding fitted. Maintenance crews were working on the trailing gantry rollers and the supply train rail tracks.

“We’ll then have to high-pressure water blast all the steel structure, give all a new coat of paint, and strip out and replace all the cabling and hydraulic hoses,” said Maynard. “We’ll also remove the main drive units to inspect the condition of the bearing so that we can best predict the life of this bearing given the unknown extent of certain rust etching damage. We will order a new main bearing and all other necessary spares and parts accordingly.”

“We had the TBM and its systems running sweetly before it hit the fault zone in December 2019,” said Maynard.

“After its total rebuild ahead of launch, the machine needed another new bearing in 2017-2018 at 11.6km into the heading. With 6,500 hours of that new bearing’s life spent, it would usually be okay to continue boring its remaining tunnel section. We’ll not replace the bearing as part of this refurbishment. However, depending on its condition due to corrosion etching after sitting in a flooded heading and having no maintenance for more

Five pumping stations maintain a constant pumping capacity of up to a 7,000 litre/min in the inlet downhill heading to keep accumulating water ingress under control

18

Cushioned seats in the manriders introduced for a more comfortable long distance ride to the headings and vital support systems including the continuous conveyor (right) have required constant maintenance, repair and patching

than three years, we do expect to replace it in the future. In the worst case, we can expect to advance 2km or so and then, at some point, will need to replace the bearing. So, we can hope for the best and prepare for the worst. Rehabilitation of the machine to get it restarted without a bearing replacement will take about six months, depending on supply and shipping of spare parts, and getting the site up and running again and the accommodation camps repaired, re-equipped, and restaffed won’t take long at all. If all is available, we can replace the bearing in about six months.”

At the downstream heading, progress had been more consistent. However, through the hard granite rock, the downstream TBM needed a second new bearing at 17,640km and again another in December 2021 at about 20km and after 7,764 bearing hours. The last replacement included repair in the tunnel of the adaptor components.

“This repair was under conditions where the necessary design tolerances were not achievable,” said Maynard.

“This dictated lower thrust forces to be applied and ultimately led to premature failure of the bearing.” While the TBM and its poorly repaired bearing was inching along in early 2023, samples of metal chunks and metal filings from the main bearing oil sump indicated that the bearing and adaptor ring were tearing themselves apart and failure eventual brought any additional progress to a halt in February 2023.

So two new bearings are needed to get both TBMs running to complete the last 9.6km of this 44km long x 10m o.d. (9.2m i.d.) segmentally lined water tunnel.

Replacing the downstream TBM bearing and rebuilding the upstream TBM is expected to take six to eight months, respectively, before boring of rock and advance can be underway again.

Writing these data down is an exercise of minutes.

Undertaking the work on the ground is a different reality entirely. In both headings, crews and supplies have to travel for 1 and 2 hours into the 14km and 20.4km long headings, respectively, to get to the TBMs, and then work 8hr shifts in hot ambient temperatures and at near 100% humidity before taking the 1- and 2-hour trips back to the portal. And while the TBMs bear the scars of having worked hard during their 13km and 22km long headings, all the supporting equipment, and systems in those long headings also require urgent attention.

The humidity levels in the 22km inlet portal heading, when the operating TBM was adding to the heat load

of the natural high temperatures of the surrounding rock, and was close to being well beyond international tunnelling health and safety standards. It was the main reason TunnelTalk was advised not to make the trip into the downstream heading. Controlling the working environment is down to two issues. First, the ventilation duct needs repair to feed fresh air fully and efficiently to the heading. Secondly, more ventilation fans and boosters are needed to provide adequate fresh cooling air to the TBM and its work environment.

Equally, the rails for the man-riders and supply trains are in poor condition. The rails, sourced economically, were to be in service for four to five years maximum from 2008.

Fifteen years later, they are still in service and have years yet to go. The benches of the man-riders have been fitted with seats to make the long trips more comfortable for workers to and from their workplaces. Keeping the workforce motivated, paid and working as hard as they must, is another concern for the managers and schedulers of the labour teams.

In preparing to restart the upstream inlet TBM first, an additional fan station has been installed to improve and increase air flows throughout the heading by 200%.

“This is a major improvement to in-tunnel ventilation,” said Maynard, “with some duct patching and fine-tuning to come.”

Another vital support service to and from the TBMs is the continuous muck haulage conveyors. Supplied by Robbins, the conveyor systems for both headings total 46km, for a total operating belt length of 92km, and have a carrying capacity of 800 tonne/hour. While the conveyors have operated reliably for the most part, damage to the belts has been significant. The belts are heavily patched after being damaged by blocks of hard rock. On three occasions, rock caught at a roller shredded the belt longitudinally for several kilometres before being noticed and stopped.

Practically the entire lengths of the conveyor belts have had to be replaced on different occasions.

In early 2023, when TunnelTalk made its second visit to the project, the continuous conveyor in the downstream heading needed immediate attention.

Andries Olivier, an electrical engineer with the Robbins team, was on site troubleshooting a glitch with the plc system controlling the conveyor booster stations in the heading. Not an easy task with the first booster station at 10km into the heading and the main control board at the headhouse at the portal. Olivier was in 19

In-tunnel bearing replacement

I

n total, there have been four new bearings required on the project. Two for the upstream TBM, including the one needed for its rebuild ahead of launch, and two for the 20.4km heading of the downstream TBM. Maynard explained the process followed on the project for replacing a main bearing.

The cutterhead is first pinned to the rockface, the fasteners are removed along with the TBM conveyor muck chute, and the TBM minus its cutterhead is backed up into the lined tunnel. Then about 180m, or 112 x 1.6m wide rings, of bolted (not gasketed), pea-gravel and grout backfilled segmental lining is removed. The TBM is then advanced back to the face with only invert segments to carry the back-up rail system. This allows for a rock cavern of up to 3m high x 40m long to be blasted out of the crown near the end of the back-up. This crown cavern houses two monorail hoist trolley beams that carry two 20 tonne chain hoists, each also providing temporary component storage above the TBM profile.

The new main bearing, its adapter, and associated components are transported into the heading and raised into a horizontal storage position in the crown cavern. The TBM is retracted away from the face again to beyond the crown cavern, and the replacement components are lowered out of the crown niche to free the hoists. The damaged components are removed, and the new components are installed. The TBM again advances to meet the cutterhead pinned to the rockface, reinstalling the segmental lining as it progresses. Once cutterhead attachment is completed, the TBM systems are rechecked for boring to recommence.

New 6.7m diameter main bearing in its cradle ready for the long train journey to the TBM

Refurbishing a main bearing, therefore, might seem an exercise in flawed economising, but the refurbished bearing only had 4km to go to the planned halt for the outlet TBM drive, and the financial powers-that-be considered the risk worth taking. A company in India refurbished the bearing and it was reinstalled for boring of the downstream TBM to restart in June 2022.

With its repaired bearing, the machine excavated another 600m to early 2023 when sizable pieces of metal and strips of the bearing adaptor ring were being retrieved from the bearing oil sump made it clear the repaired bearing was not going to make it. When TBM operations in the past have been shut down for investigation of micro grains of sand or contamination found in the bearing oil, it was remarkable that the 10m diameter hard rock TBM at AMR was still inching along at all with evidence of such main bearing damage. But it is now stopped, and while the new bearing is on order, the full process of removing the segmental lining and creating the cavern for undertaking the main bearing replacement is underway.

Looking toward the face where the new bearing has arrived for being lifted into the crown cavern, to join the new bearing adaptor already horizontally in the crown storage space

Segments are generally difficult to break out. “Previous bearing replacements have been a planned process and the segment lining was not installed as it was known this would need to be removed,” explained Maynard, “For the current downstream heading process, where the repaired bearing failed quickly, we have had a section of about 60m of segments that were backfilled without grout to remove and another 130m that were grouted to break out.”

Jack hammering was required to remove the key segment and the other segments came away leaving the grouted pea gravel either attached to the segments or the tunnel wall depending on best grout contact adhesion surface. Jack hammering was then required to remove the grouted pea gravel from the tunnel walls.

The four previous bearing replacements, together with other causes of long delays, have cost the project 2,248 days. The new bearing for the downstream drive TBM is in the Robbins stores in the USA ready for shipping and once the upstream TBM is boring again, attention will move to the replacement process for the downstream heading to have both TBMs operating again.

20

Lifting the new main bearing to its horizontal overhead crown cavern storage space

the control cabin at the portal while his workmate was at the first booster to coordinate their efforts.

The glitch was resolved, and all was running smoothly before the bearing gave up, and everything came to a stop.

Olivier was then assigned to the intake jobsite as the first resident in the reopened upstream accommodation camp to work on the requirements for rebuilding the flood-recovered TBM as the first of the two machines to restart. Any Srisailam Dam components needed and not yet available onsite will be taken from the downstream TBM as it awaits its necessary new bearing to be fitted. Removing components from the machine in the longer 22km downstream heading and trucking Fig 5. Tunnel 2 and other project works are complete Srisailam hydro station them through the tiger sanctuary to and awaiting hole-through of the TBM drives the upstream portal jobsite, does the TSP-predicted hard rock on the other side. Then off seem to be a taking two steps backward to make one we go again, on to better things.” step forward, but it will get the machine started sooner than waiting for import delivery from overseas suppliers.

The latest report from the upstream TBM site is that “We are well into the rebuild. Along with the predicted later replacement of its bearing,” said Maynard, “we are planning to add Robbins two-speed gear reducers to the new gear boxes. These are part of the Robbins CXR Crossover TBM technology, and with these installed, the plan is to bore our way out of the stuck situation.”

“We have completed controlling rounds of polyurethane grouting to hold back loose material and stem some of the water inflow, and our target is to be able to run the cutterhead with lower rev/min, high torque by the end of August (2023) to free the cutterhead, draw down the shear zone material, test the cutterhead drives and essentials of the conveyor system to confirm that we are succeeding with the plan. We will then follow on with commissioning the remaining systems to start advancing to get across the 3.2m or so of this fault gauge and into

Current overall state of play

As the TBMs have struggled on their long headings, a second tunnel in the Jaiprakash contract has been completed. The 7km long Tunnel 2 runs from the long tunnel outlet balancing reservoir on the Dindi River and into the distribution canals (Fig 5). It was advanced by drill+blast to an excavated o.d. of about 9.8m and concrete lined to a finished 8.75m horseshoe shape.

It and the Dindi reservoir dam, which is also complete, stand ready and waiting for the long TBM bored tunnel to hole through.

From renewed commitment to complete the long tunnel in August 2021, it has taken until late 2022/early 2023 to agree on revised contract terms with the Telangana State. Jaiprakash and Robbins are both in significant financial deficit on their continued commitment to the project. Negotiations have had to address these arrears, including stagnant or unpaid wages for the workers and engineering teams, and arrive at an agreed plan and investment The 67 front- or back-loading cutters with 20in rims on 19in hubs that dress the for rebuilding the TBMs and 10m-diameter cutterheads are refurbished in the onsite disc cutter workshop bringing the support systems up to efficient standards.

In addition, a more realistic expectation for TBM advance to the end had to be discussed and agreed as the basis for cashflow payments. While 500m/month/ TBM may not have been unrealistic at the bidding phase, double 500m/month and more would be needed, and regularly, to make up for stoppages and downtime to achieve that 500m/ month as an average. There is also the factor of diminishing advance rates as the headings and the supply lines lengthen.

This is illustrated in the fact that the best advance rates for both machines were achieved in 21

breakthrough another 36 months or three years to complete. With two machines operating at all Rate For a single TBM For both TBMs times, and from the time when both are ready to restart (a minimum period of six months with a Per day 38.4m 55m new main bearing now for the downstream TBM), Per month 542m 753m this would reduce to 15 months at 250m/month/ machine or 500m/month by both machines.

In a quarter 1,316m 1,723m “We are though heading into the most difficult part of the project,” said Lok Home, President In a year 4,547m 5,087m of Robbins. “The interface of conglomerate between the two different rock types of the long drives lies ahead and as an unknown quantity, it 2009 when the headings were less than 5km into their is expected to present extreme geological conditions.” drives (Table 1).

In all cases, the agreed scenario is that the work must continue and the project must be completed. To achieve A more realistic average of 200m-250m/month is now this, the advance of the necessary funds to make the being negotiated. With 9km left to excavate, at an substantial investments needed to move forward must optimistic 250m/month by one machine would take

Table 1. Best advance rates for the TBMs

Jaiprakash and Robbins Project Managers and site personnel

Anil Kamet, B E Civil President, Jaiprakash

Deepak Jain, Project Manager, Jaiprakash

K B Singh, Upstream Site Manager, Jaiprakash

R P Maharana, Robbins Stores and Spare Parts Manager

Jaiprakash and Robbins day shift crew 22

Rituraj Deshmukh, Geologist, Jaiprakash

Glen Maynard, Project Manager, Robbins

Andrias Olivier, PLC Systems - Electrician, Robbins

also remain flowing from the State to the construction and excavation teams. The renewed commitment of funds to the project by the State of Telangana has increased the value of the Jaiprakash contract to INR 4,000 crore or about US$800 million, doubling the value of the original contract value according to Jaiprakash B E Civil President Kamet.

TunnelTalk References •

Robbins introduces mega-TBM advantages at AMR - Jan 2009

•

Second TBM assembled for Veligonda - Jul 2009

•

Hybrid EPBM for mixed drive at Sleemanabad - Annual Review 2018/2019, p65

•

Nepal proving TBM applicability in Himalayas - Annual Review 2018/2019, p19

•

Early breakthrough in Nepal for Bheri Babai - Annual Review 2019/2020, p68

•

Nepal prepares for second TBM waterway drive - Annual Review 2020/2021, p34

•

Crossover XRE for navigating fault zones - Annual Review 2020/2021, p54

• Breaking excavation records in the Himalayas - Annual Review 2012, p68 The experiences at AMR and on the other long TBM water • Video: Kishanganga hydro headrace TBM drive success in the Himalayas - Feb 2021 transfer projects in the area • Feedback: Optimum advance for long distance TBM drives - Annual Review 2014, p80 (Veligonda and Sleemanabad) and on the hydropower • Automated forward geological prospecting mounted on hard rock TBMs - Jul 2021 projects in the north of India raise the questions again, reported in project statements, but these seem to a of how best to address the substantial unknowns thing of the past. On many projects today, funding is so and risks of undertaking long distance, geologically hand-to-mouth. unquantifiable TBM headings. Regardless of the amendments that might be made to contract Comparisons with other long distance TBM drives of the documents, the need for future projects is to start world can be made but what do they say really? While with conservative estimates of progress. Achieving the data can be useful in gleaning the best practices better advance rates is far better than falling well short for achieving success on each, it is a hollow exercise of expectations. if only meters/month are compared. All other common denominators - including leadership and experience Tighter control of funds from the start is another takeaway in the owner organisation; contractual arrangements; lesson. Money can be spent liberally at the start of a funding security; logistics, mobilisation and continued project only for the job to become starved of vital funds maintenance and repair of equipment and support and cashflow when reality sets in. systems; and labour expertise – must also be included for any meaningful comparison and discussion.

Commitment to cashflow is understood universally, and while paying for meters advanced is justifiable, it is the The one assured common denominator on all these highcashflow needed to get TBMs and boring back up and risk, long-distance TBM drives is the determination to get running again that is so much more difficult to approve. them done and to never give up. n There used to be a line-item contingency reserve Inlet portal heading towards in-tunnel junction of the two TBMs and final breakthrough

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Most of the tunnel and fine to medium grained, station excavation lies in favorable, St Peter Sandstone, well-rounded and uniformly graded a deposit that extends (45m) beneath the some 150ft limestone. Groundwate sandstone, about 2m below invert level, r lies deep in the relatively impervious and a thin layer of Glenwood Shale water table in the creates a perched open bedding planes Limestone and in of the Platteville the overlying alluvial and glacial top soils.

Top of rail at the During a site visit center of Lindbergh Station in July 2002, the (11.3m) beneath the is about 37ft first 7,400ft long o.d. (2.25km x 6.5m) limestone cap, which x 21ft segmentally lined thick, and creates is about 30ft (9m) finished and the running tunnel was a flat ceiling to the Herrenknecht EPBM station excavation.

(152m) into the parallel was Client for the undergroun drive. The Obayashi/Josome 500ft JV had also started d works at the excavating the 14-6ftCASE hnson Bros Metropolitan Airports airport is the of the 525ft long deep topheading plex Commission (MAC) STUDY: An team x 60ft and the design for the design-bid-b ning, com extensive Seattle 12m) Lindbergh Station. wide x 40ft deep (160m uild contract is x18minx began light rail city plan nsive option led by HNTB network the Corporation late 1980s with specialist plicated the Seattle and it is expectedThe in subconsulta least expe of com with excav nts Hatch Mott downtown MacDonald is highly abrasive running ation is a story to provide the lk geology. and ventilation; bus tunnel for tunneling The alluvial material of cutterhead toolsadvanced tunnels of the LRT pass directly accommoda of CNA Consulting project s. Today complete changes beneath the pressures and across the central te airport n Cha four mandatory both metro the USA highAusti hydrostatic that at least two in oulders, lace LRT alluvial valley are tracked by athe tunnels bus beneath servicesthe taxiwaysand The contract specifies s Cityp moving exclusion will allow of NATM the were the treacherous favorable and mark(Fig 1 toptrains will be needed. zone as the TBM where conditions right) and electric in abrasive alluvial materials on the underground comm of the Dalla application the beginn with man entry inspections in areas TBM tunnelers ined the tunnels air pressures of less extens on diameter. ing of severa Y: The story and another comb in greatly conditions awaiting An order running Diego under compressed Transit, includ of thations There San STUD of or, in E size the l TBM intervention ents project LRT safe were corrid ever CAS outfall t the and ofand ing TBMs erns, built. system the, deep placed for two new hard probability fornot South Bay ocean ghou arrangem LRT station Sound we visite too many station on the highconc While sourc bar.

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After Line’s new it onents act edge on with Mott MacD with Delo management with JJ&G, the Seattle Transit LRT, 11ft i.d. machine y, built alluvial materials of the consulting taking n Ham of the Nanc run from Rapid Trans million contr milesct.long, the busthe it all started bottom in mid-M 3.5r proje depositsto an in tunnel truction Expresswa delivery offers from iated At nearly s Area mix of thealluvial a singl onald for WCS pton Asso of the 312ftay, we plan y with the starte through a complex end of s. for cons 67-mile Dalla work on its $86.8 of the TBM water recla its assoc four-lane to launc e site office The cut the facilities plan studied ciates , tunnel a ages. n is thatover passes O. and July, the d (95m town n from Both licatio h tual s ent deep River which will the first 1989 starte ) deep a implemto statio ased location even projects and the Tijuanaincre constructi mation cente BER d inestuary to by comp TBM Rock downipal the be ahea Chicago underground while acros millio of(P/CM) washed at town McKee (CDM). mouth SITE VISIT “We RT: nOCTO depreresse is to beofat the The princof manag d of our dale Shaft by at tunnels on itsREPO be down Healy of flows fromon of the pumpr (WRC). At one the R.M. Claytare Dresse thes, seabed and r are, in fact, is to to from sands Camp REPO RT: lth baseline VISIT $18.8 Cityplace runningSITE the ng composition . granular 6 by andclays on Nut late 1950 on work onwea end ay statio d the built runni River the 1985-8 and DECE shaft for the of twin tube y ahea progr cons Comm of silts on was Nanc and freew m) n is unde fine the Trinit sinking MBER d of sched tructi tion, am. of thefrom secti sizeable y Cree ado starte -lane ranges 1987 way. cobbles shaft treatment plant grew, a second s distinc and rway to WRC eight (6.5kin which High path 3.5 miles elps of Color bridge over the capital city the WCS on of the new, k project. dubiou gravels mile sewage of the the region the deep alluvial westFrom a 200ft being new underg element and site mobilizatioule at the mom first oston, theestab loose ofNorth the 4 kee, shares As dedicated At the otheraccept ess the LRT ts,lished forMilwau After primary Boston’s etunnel fromround Hensel-Ph 1952.tion MassAna O project will anticipated. n, but minin ent with we are succin has arethe rity, chuset 1968. nd each the in to build boulders street Seattle and the by Quincy Massa been treatm the end, begin autho d o large beyo outlets act in futur looking pora Island shoreline, ’s the the ing just charge Chicagss ont . At the answer toTBM to for Island contr ent buses and Transit the seco is sinking the back from at Deer the ged through short for 60-70 g is the critica withit has cities by incor do 1 mile Formation tly built toplann Parallel 1.3 TBMs WRC site, plant for along network, urban rema Diego in on only set about round Sanfican was een proce l waterfr thesigni Discharge ft (18- 21m)/ s Area Rapid LRT y (EPA) thethrough week plant schedwas betw -the-ctraffic an uphil nd WCSO TBMClayton acce mile ating US pass under the Agenclace, to belowisofdischar an long maximum.

(2km) , day rge with lock onconges ule. We “Ideally , the Dalla a closed, 230ft frustrlarge the waste ncedand designed those ems, ss shaft Obayashi/ integrated ation l gradient tion. about in beention ing,1986 a fulllong discha Cityp streets Protec will mile influe often among ns probl the expect tunnels At sion pressu three seabed the screen will is be For DART manage an by excav day the one recep the of mental from and better to 50% of week uling theends , up 8hr ent courseNego rized tunneli operate below provi to the s. tiatio than leading afternoon in for ate 23,00 central district which Environ n caused to 158ft in the watertion shaft to have lopm shifts Station more 45ft at up harbor. the buses d the the tenanto federa expensive et . Part of main deveits water and lsched is a main of little ages in y. in 1983 thes,pollutio shield Shaft will 0ft (7km 2). n.

(65m bearing .ground statio The ng215ft n issue present 4 ce on each/day, will 1 and offtenan In the waste out of the 6 days/ about ,” said John the agree would e into (FigsLRT the streets ) deep Jim once a day take eDART Budg someth arduous, ing the ,agree nd pass desig sea level up advance first mile/hr place TBM, sswa ded. rgrou south North Aven) in of anand dissolv ce contr and techn takes mach a long, at this point.

Atkinso rding to sewag MacDo to its 148ft will carry ing and iently commu ment mile/hr in increas s and tideive Pionee 20,500ft oflaunc ician on accotreated nald, Project and that this is ill-foun the Expre plannof act with tereach hedr at with Herre inen,on“but there e the loper elmed.

DART: to dilute n with unde ofebbing traffic flows comprehens peak with athe insuffic s, but and deve period (6.2k er overwh the Rock ue side that to arrive with complex s proves many are (45m) deep nt forl abilityat Manag Cityplace delay nd statio studies mach nkne been s. nkne to one Herre full-tim ’s natura sky r of beache investigation about either Parsons infor sitergrou sinceunde dale Clear Cree m) chtscrapers along deep tie light an enience backs on the designer 12 e Herre Intensive long and time The , owne Manageme green n on better excav together cht. We ine. We also have rs, onethe Waste anchoring by project on harbor withnkne “Two TBMs the tunnel pany cally hassyste Tunneling these k the uphill gradient prepared 7-11 conv m beral finishbased the solutio high costof Constructi reporttowe chtwe need easy will the LRT a majorit both r began in ated and they date, in as far ofas can tion shaft geological to prick are a minim route and recep hland Com waste biologi to re that, chain caused tectu the WCS access group r contr indicate Atkinson/Dillin November will supp pay a fixed cutte of s, CDM to t outfall. To outfalls y act archi . been given of the startedate.al the Sout Science problem and of the tunnel Director ational rdfour ” or pressu reaches to theum n, ties cost/yd g the Assembly requireme deal 1986 when ventilation effluen d ly all the 3 intern face. retur gham authori Martin, excited to have construction chose Knowinthe by the isOintunne pass through individu Engineering 1996 s and lowest of of rock JV the public completed Also, long-di two open-fa dry, lscompe the Guy of thewill asntthe cutte to lie stance14 long sea tunnele ly under uledan the t tunnel work and said consent ibute 1towa oving paren to get excav an avid it takes nt 3 are eight compe ofwon theTBM to get predicted, first F r need civil and case, contr tent ground “We are contrac hold treatme and machin the sched of large, slow-m s.” the upper saidced current decre other below the are about byOften Bostons,’s t with the ation wouldforReaches geology.

Ken at Rock are ready only inn. which there water millio with e facility h, with deadline the, we Johnes material part $61.6 million ting bids at $44.2 the largest theaction. quite Indifferent breasti 1980s, dale Shaft store sible operation conscience into last and t $40 the in oper of WCSof are n whicand ng plates taking the more respon face ston, sandy d abou of 7 Nove ingravelly worldw be ide, ated ia.

O the thewet ation and into contr tioncost to mber softer scale tunnels much seaonmust usual 30-to-3 Engineer’s Estima million, well , theOf the statio porous City’s Proje in agency of the gripp act.in“As operati ofgranular Founda forcengthem rolling , Austral anaestim nts, willpressure in theervarious runni a the State a job of this on.

6 month constru te. Instead sectionmachin ons.” in hydrostatic 2007,” well as conditi in Thefullvation on sued beSydney ct Mana barLaw ireme to was 7requ jogger and Agency secti e. lace ction ed nt Conser and its beach of ion the scale, nd going anticipated the n The Cityp are constru was “techni s. edown Protect 2 and 4Act me, ction period , Seattle Metro, proposals, TBM drive ger for the all treatme tight 17 month statio m mentalReaches the schem now involv under ing costs undergrou forservice cally syste the one from material sewer Wateral sche silty for s plan has with flow from expected. the client, s, the contr and sals progra Cityplace nd sections propo only e CBD is also Seattle superior andwith starterl Environ origin permeable by early l inches ted Robbins CDM facilitie Federal Clean the )Federa r Island a town r theless the reduc act Federa (32km 1972 competent, eleva sued -based making most econom ed ,with 1990. To m to have the system imposed a Apart of the 7-mil to spare down Unde turnmile on Deer an Island in Boston undergrou n of earlie 20 ng themore State.

In charg ical.” the y on n Deer meet place t reliable the in enforci (right to Robbin ) by pressure. in was deliver on not the (EPA) for(11km this, Atkinso millio service ary machines, s ) moderate harbor by suing at abou y easy and ge taking d Expresswa more an order DART the $218 d when down versio sal for atedded this secti The machin and second n neede one and deliver respon quick. t 7 miles impose ver esse ity rundischar propo was EPAestim 3, thereunder es are quite 1989,ces andcarried 1depr ed quickly for each tube, design d two Island ns howe After primary 8-10 miles out to in eMay 1986 InResour was to of reaches and thewas original rground for abou schem of the nAuthor Nut open-faced finding different . conditions long tunnel. ged estio (CBD) and expe nsive the t and ed, built suggestio . The median mile gravelly Water e excavation (7.6km) porous, rectify rtmen district the a sugg foundIn District e theTBM an CourtMassac ran unde plenum, will be dischar 110ft of water where 5 Thesor m to abov the backho shields. To provide from the more familiar The geolog to be husetts progra effluen business oval for such s the In t using a no ture into the way median. the Depa man e paddle nt, de can freezing. ent y be High strucentry which had llytoat-gra central limits in about can naturally dilute of ground on the treatme implem -type excavaoptimum face access tripod of clay with the is mostly over-co . Appr n. the assistance a alternative ) antia had the harbor inter-re the State .beyond ocean without nsolidated to require 1999. millio or at grade water table .7than (MWRA $1.1 billion cheaper chamber, subst no$828 of the is expected sea built two other acting hydraulic tor is mounted on , ted by ment entry sands, silt 14 of Pionee runs 47 balanceLRT lineswaste (Fig 1). and rejecman d at later 4, safe n by and cylinde a ruling r Square Stationrising close to the and thetoalign machines face. ical were theecolog situatio denied now being built and reaches 2with Theremaining is price Washington the court along ed.the water table to this design rs. Robbins has surface south the air to help by holdthe (Fig 1). North rade There will reach DC Metro complyof compressed is of-ways residents side of biodeg todegree , one used scheme Coordinated e was and of the Station Caracas Metro worknd. y Deer Island facility in 1974 and over consoli well below the tunnel thergrou either rail rightromis on the sswaed unde time to lose. newly ,formed , the the other scale busin be of noess boxes in 1978. gallons/ dated materia Expre existing elevation The to e left propos thethe , the 1989 a comp used on the has central ts dated in ral and the dry ted, ls can be thedeadlin sswaydivision on costthan 1,200 million part of 37 June a short nsultan system such mmo ement In its very hard.

Expre sub-co When integ comple acco The 21ft (6.4m) manag y of more l and constructi mral ged ative. From lace the Cent erciaers d be atedcapacit progra Being anhave own ts enga a peak woul Engine diameter, (HNTB) g. and estim comm North At Cityp ptable altern sits r an doff a ultan Kaiser the y thrust cuttin d was 140 ay onstructions, with tonne, 600hp capacity of a majo multistore engage by cons n & Bergen highw truction boxe is no acce route follow Cityp lace, MWRA 2,400 tonne s Tamme mme/cthese two shields have designed their cons the Needle have s rising itsa progra via the 20 project, million, were through Howard Both as district, comp t and thrust rams 62 built.1988 April 19 passes development in be t to Departmen y program. of $189 yet which Geotes ential Highway which is plans.

Expresswa by the and resid second of ed in the y the 7 DART LRT incorporat towers, Expresswase ct on the Central major impa North and inten tion of rtment, reconstrucHighway Depa State “Proposed Texas by the

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collapse it not back CH 1999 under control after Authorit•y Construction Manager: in now why was in-depth of an Water ED: MAR subjectTrent works at Heathrow is theSevern The to•that Taylor Woodrow station excavation &Safety being Client:the sites.answer now UK Healthr: G nnel portal H Hill & Sons tunnelling : Eurotu faultless.is ners: Contractor: investigation by about October 1994. •The Enginee the intended of which is ingreport ofClient • Design-build ENT: JULY r: Geostor the The £20 facility in its Desig Consult projectoflooks vicinity of men and 1983 when •(HSE), the & Co of the site for the depth andtunnels out uced from materials and for million project, kept million yet.

• Contrac carried e Ltd simple”, undertaking the and andExecutive Mowlem 78m actor introd (TML) Balfour Beatty £15.1 is “amazing d 1994 AND machinery ventilation, with John months taken for several tors: according ass awere Contrand maximum a joint wereLink of Calor deep x 1.8m diameter of • men bore hole reamed ly coal interest, (6.5fissure started brought to the application Contractor: being collected firms to•appear samples to Tom The Resident Gas,a with hatlling system -Mancheby eight unlikely andthethe FEBRUAR surface via two a 10.5km h the wet • Thyssen and Conoco,with is still Paterson, Wirtha reamer Trans 160m. Core is impressive 60% consists Mining Engineer to build tion (p56) the start 14.5km 40% tunne were complete /Pigott Consort l throug Carsingt resources aton Material evidence highly likely long spine roads examina Y 1996 contract of legalthe tunnel ortium contract . The top . ners: t at chalkproject readythe to tunne possibility share, has and with gs.detail for constructed in as a result remains of alluvial ium: Shafts to remainin , causing view, the meticulous. drop coal isCons l Desig from • Boldon 20m site and the identified proceedings al in headin the ls) production onto hard planning to store g the the and glacial longofaqueduc rock well below the upper geologic Tunne moved through the tunnel Tunne attention mile)ions ct Japan was Drilling: Service point of that ethe of the a conveyor g foron next 200m le deposits and the coal bearing scale rtium landward the in the crossthe slightly to avoid stages and instability tenderin u d’Étud into severe indicated availab technical Tunnel to conne for the parties involved. made clear toA conveyor adit chalk strata. remarka condit is the an event for transferring boreholes adjusted • Conso • Fairclou While (Burea ire has run sea andofnotexcavati through borings t to be or struts and readilyon onto aon to construc rom a system will bring which stretches Upper Cretaceo conveyor hen gh: Cavern bly quickly. e: BETU ion whalings in Derbysh alignmen in either their under Channel Calais in France Therefore, it was the driven mostly the coal the spine tionof nald the early The Francbe us complet g props, isedup the two 1-in-4 need for s were tunnels Jubile theunderlyin east under for the roads and hauled Seae and to ofs, andsystem be used area.

McDowith wouldshaft undersea avoiding d to In January drifts to emerge areddifficultie years behind have the North attending an all-party-organJune to Projec affected Mottseries tunnelsrescue the surface could not Denmark as two journalists t team, Lineinto UK: Grit updiameter at the was Exten in Englan 8km at Gascoigne1981, contractors would Gascoigne Wood 60m as comp ng in beThese TBMs water much ean end construction. angles t, the of as Dover briefing in late may granted by Woodplanning six exploratosion and (Fig 2). When Fullface Ashover the Londoallnonfive From appoin site where all the permissi andthe French at shallow Germany. amount may to Europ dateand l and h the lt projec JLEWest It excavation visit and technical was Glanford of core constr ry coal formines budge Under throug ease Strait crossi to the are producing g tunne a difficu natural ground is also necessary to e, planned pt that of the large of access site uctionCouncil es, these dipping the excavati about the causes handling, storage and loading main series groun t as thedchalkted byborehole at Borough ent runninThe ls. NATM because full capacity Seikan schem passing originally1970s attem use the was not well scheds, it was found contains several ofby the water pressure to manag on of theextens facilities 115,000 1996, that questions by mudston equipm late 1980s, Selby porary es n for marine would as much. lty , awarded of tunnel. are located (Figs ardoftunne chosen theonLPG.” s and the lack bands two approxim ion,million mudston new of Applicationas its progra pre-grouting. e cover ule. deliver aquifers 1 and 2). to contain with the or along lengths greatg difficu m 3 caverns will from and the costs thereof g tunnel costing twice 10 The mme setately expected, the contemexample. The UKedlandw cular fashio strataspecta 16marl contract and collapse principle specified and tonne ions had the a of runnin long very km-lo es, As coal 21.2m the however the 53-mo under soon , for ground a x rail for Conoco for year, mostly for use startowned tunnellin is as spine roads reached in isolated d interbedd assoc ng hard more to contract s are: i.d. land When choosing sandston to do long The journalists tunnel The fractu water nth red condit (Fig used in and 164km Japan face bytothe public pressure, • that a higher funds t, except the storageset itself Authority programme a madeflint Central UK the Electricity not be by openin first mine at Wistow, lly answered. time. two 7.6m thensiltstones service one containe on the Water to the 2). iated cost , acts increa to in this storage Client of drill+blas Generating ofBoard of the survey 2was ed with section) x against at that twoletunnels, case liquid a tough central thorough briefing for achievement interbedd g, it knew coal production and butane gas facility, the ofsite : JLE also specifica Severn Trent 285psi, comprising an UK The use propane thewere ses Governmen at nearby LPG Transp chosen, calls for 100psi needed geophysical Marl stratum task. As theSite diameter were treated to a from excav power stations.(Fig 1).

A ation ed by high (252m 14 large 4.8m i.d. it had geology confirm the 55m Londoto Manageme work er. It was ances, was ort throug propane tochamb other notab connect Chalk Mowlem view of the current progress and to a visit it began with tunnelling of the soon weak, most t Depar began immedia vice versa. x 15.4m investiga In time or is large the Two civil John the and a n circumst perhaps liquefy the and French nt 4.8km, as importan Unde the same bids.

30psi in eable, spine h team constr tion let in late project’s tment to liquefy the project's to d wide the continuing to which at the crossoverthe design of short of roads In the interim thetely rground on 1). the other containin out due from the success the first of t consider ation of pipeline uction for • Contr and later the gmajori connect the remaining million contract butane, public fundin shaft(Fig conveyors 1993, into various sections four sea depends 3.6km and it. The was aligne contra lly an imperm excluded Ltd le for rapid also scarried under in the a signs • Excavdiameter excavation spineof to sinkand Its aquifers £2 “One ation. access ty ofpresence of actorsthus how mines. cts borings. During tion, ls under e problems expected aunderground at theg acces for investiga shieldwill transport a great natural is genera fourconstr g is grante tworoads deep 140m of the most tunnel al workin access for each highly suitabzones awith major geologicwas to modifi both enginsubstantand 3km of the 1.6km x 1.6m uction specify on-going works. Knowing exactly is essentia extent 66m which extensiv from aspects shafts, rail tunne the work princip engineer cavern, was main site d. ial their desig startecoal minesalong te to us rock on impor al propertiecation used again ed as they come decided to l. “Unlike eers: See a shorter more gases, excavation d.

Thyssen as the g and three on line andawarded ated. is also side workmanship andThe south drift tunnel is being Roadheader tunnellin All following the longto land By from s. Petroleu clauses other tant almost all following n-build explore inclay en-roufaulting, it was muck homogeneoalthough fractur be anticipThere theto end consultinsea of severa the contra stage, g jobs, we current quality of driven the /Pigott behind alignmeasily constr the of form, themore Consorti m we 500m on method. best the the site. what the 5.8m diameter borings soft in gault end. The headings. to pages tunnelling of water option, three under from with stored welcome l the um. uction ent 5th introdseeping Januaare ster.

Nine to two lofterminal based excavati Hill in ct tunnel the docum takes sump entaryCastleadjacent the sight s for eachmachines tunnelling, inflows were uced into surface Robbins TBMborehole downstream for itsof Manche supervision differs liquefied in their workdeadservices ry liquefied total 230-w Tunne construction with be ent was was in a large supplem neveran average of considered stratum headings. will based cavern landward tempera 1996, the by eithercondit workscorrid and end levelH Hill & Sons continue!” into the ions, is The need to cased about 100m/wk. the collapse may Channel was moved and or were orted to the scheme eek corrid long tion it was the ground high waterthe Chalk Marl contra lowering booms were fortransp on confesse Strathclyde drilled or by compres programmeweek ture 117 of theira stipula of Anderson nt would Theconventi below seais G or beingprayofit up to 90m the UKOne portal was going on before Boldon north where detail were made.

ICE conveyor by d Paterson included surface, n also is: the implemctor in the Drilling under explained in some tunnel, some 70m parallel, its originally Coal Board tionartthat Souththe out sion.would Site investiga and excav three the shaft wide, the muck was Tunnel Following a maximum 115m d. Tunnelling . equivalent it is usual from of site andentall equipme using portals grounad On the 1979 ofand l mentio be bound The incorporates oil well type is being 57 x onal 75% comp known, but it was times the be excavated using line ed to National plishm theselection lies during to ation to store ent 16mm the pump stratum through this out in familiar sectio of speciaarea of surface steel ropedrilling to accep ydistance m3 some the seabe a Titan 134 roadheader The the bottoms water along and accom flamepro now being progressed alignment to approximate themanin accele in finding for thet caverns e ofed lete. g incarried refrigerated provid cords rig. n was tunnels are going detail how downhill across the full Worthwhen an Of the the ration a beneath making about half and ing y of the work width£4.5 ly about tanks rather 4.5 ,million the tunnels The JLE depth. to workin available. of deep borehole whose is sufficien of themillion d with at a1mlarge intervals tunnellin pressure logistical necessary servic site 30mm thick many the rate of progress was awarded water inflow progra original. slurrie and 75m suited UK s as strata, with the possibilit belt.g The t to containfor contro vessels. Cheaper and that it was sinking standard contract planned • The Projec thanshown Anderson construction al in in so at Strathclydeto Cable the ce.

Faircloug is different from the t, generally about 50m/wk. Coal in distan t team g the to be practicmme s highly tried and readily the LPGlling groun methods availab themis under was three long holes 1km h, the stillthe Measures cannot be extractedfive tenders. Geostore the aqueduc Belt for dispos as to make minim system is cost lowest ued conveyor ered.

Coal estimates great to store whilein about l shallow supervising UK side, of runnin pressureas reason larly the ising but not d movem of appoin remarkablyof d until the cross theundergro le contin North Tunnel is acontra were well the cost additiona seepage waterable g pond grouting on the scheme , a licencee ctors in largerable,” French being encount particu of adit connecting steel These used on of settlem ted ent and geology Robbins pumping company comp changed und rope Projec NATMAqueductation with several settlin ent, nearly methane capacity said Mike were accep from or reinforced specified theGiant shaft rescue trains, of the TBM from the the two conveyor which allowe facilities. techni belt t the spine roads and ted consu excav Geostocleted tunnels.

Manag on ation ofir and ground In some access The cavernJLE. have extensive designed cal doubles speed with two ls Liquefied all have Engineer also What had l advances most Reservo lting sea Smith the k, lling rapid of stable d prohibitiv bore time steel been Applic cases er ton the which roadheader obvious, canno tunne hole ropes and for most under , JLE’s connecting diameter supervis for Const tunne gases • been of origina enginesuccess and sealed, this may To comp 57mm allowe e. has l in logica start,tothe the mine above is 1. Carsing To and prepa allow grouting fully tstored the same for thethe ed a ersexcavation ers and pressure of several require extensiv supporting tunnel regime to ensure modification /week the detaile ruction Selby ensate red the tunnel completed. construc predic used initially the techno ng high speed 428mFig operatio spine lightweight LPG caverns, On leached be jeopar cross while at cing service roads d indesign projecgroundw under alling area which to tion ted settlem e for areas 1in-thick lex chamb clearly most expensive, um and breaki 60mWistow mine t prograater. “Wens and ground The steel dised by fordocum of the the The chalkbelt. a projec contra ct many years s cavities in salt t s through ropesincluding in northern a maxim a maximum 8h high,alteration the comp ground marsh record came online in April ent may our are formed amount of the original scope of works is mme deposits condition spliced regime the advan excavation where t oftogether one events there entatio grout of the At its this in size side of findingcontro g to around the toadvance under to form an France, finalbut to be almos thethat still prove have forand engineer l. the n.14.5km built in the construc isrope suitable injectio Cliff. This a purpose The and the consultin length, with the expected methods caverns of the the UK 7 days/week with eek) buildin are within proven been . Associat endless dealtwo accele geology tion of water comp concurrent er, which had of the conveyor at -built undergro each x 30m deep cofferdam in three stages:diameter too speare will station g side. unfore edOne be lexity, come intobyn ground of the shift/w the contract and water contractual ration construction ntally the tunnel; easydifficu of the airport seen This is done of itsits und clause most advers no s include at Shake al working treatment (24h/day, maintenance kind month task, as longest used to curtains groutingalleries water. ation in operation their own. over chambbefore arrival excav of driving Central Terminal Area (CTA in of g methoabove, the e in Europe. ete segme The is useful s whenfacility TBMs lties.Paterson explaine South Killinghohas between River Humber, a newOctob LPGerjetty Two effecti was“The ds used caverns.

1994onof re in advance are built; and radial 1, 2 and 3) to almost totally permeation the princip of the six downtime service Similarly, pressu the collap over the grouting olted concro.d. 8,036m. geology were being d:the recove ness complete on lme, and At the nes. ve d. rings NATM the site neither non-b pipelines marine Terminals on must on the the ry progra of unrelated, se enough connect the l of machi negotiated.” water as the groutin JLE includ grouting be compete excavation gallery strengthen ges and grouting launch a fully to remove the extent tunnel muck will also km each is expected has been complete nor g, mmes Airport which facility to sea tunne 22km of 179m/week nt e concu work extensive excavati encompass and TBM allow the Conoco loose a to stabilis Express but ofrrent, Only by cross passa had to share cing after the lining vs be necessa course and 18.77 Settlemen and to complete lined under l average was l south. e and water disturbed ground. grouting of the the roadhead refinery Rail er on and the Because the geologic Heath compensati an immed also ry. advan 17.36km collapse and the tunne rowmore and Since limited the t cont requirem g ducts al propertieon groutinbearing groun l site are so iate and Link tunne introduction Groun with the the effects tunnel, best overal running ent, the drivesstanding at the edge of this huge excavation rn slurry relievin projec support A Titan E205 of the Jubile s of rolthe d movem the more responsible l progress l to porta n times gs.

TBM, marine t. As g for mitiga d, of predic bay has been importan t, a geotechn roadheader e project ent side, mode pressurised econom ratesbeen consecutive interce job, Mowlemscale be appreciated. "The upper the UK induce in the from porta ted transportatio g tunnel headin Four which South ic its contra one French establish excavatingteam volunt reaction, the Tunnel the have dpiezome its that bid the couldWork of by excava Tunnel e (EPB) and ed,pt ground ical volume losses ting work runnin On the the 9m wide eight firms arily instruc JLE projec the most critical tender. ters tion has Channel cross marine water-bearing ground re balanc Of the Waterloo ctors to stop to measure equippedmovem mining with ents as and x was soft outer lowest 20m second tedtop heading four hand 53km long and Londo thethe and through NATM 5m high ground water they occur. beneath t team. The Line, concerns for the and earth pressu many lateral Compen stabilized by 1.2m with shaft ducts won of the integrity er 1981 gravels work at ,some d the rescue • The x plishe with visible is supported and running 30m deep central on years.

Septemb section re relief access sation and safety n Bridge to of the oldest bands important as it does 60m diameter Comp ls. in shaft, pressu accom original ed in four piles which interlock review of marl started 1km of 19m diameter grouting tunne Fig 1. Trace of the Geological , historic of the and and flint presentensation stages of diameter the is on the one toSecant NATM ges and main bored to be complet different works. a comp ally most Alan Powderham, under grouting and subjected prestigious, the only work had designed for JLE in the About centres," explained all of which were access shafts superimposedpassa areas of lex chalk 1.06m tunnels, and to the is princip techniques Mowlem plan was the four portals the three at that limitation exercise manag London, outer platform linking of the Foundations time and been completed NATM surveying yed The from ally to ensure ement tolerances most stringent concourse and dersDirector Managing work collapsed advanced a tunnel roadhea decision-ma and co-op in multi-level thegmain tunnels damag the works of Mott MacDonald restarted although revise the delay headin ling projec ever before • The ce systems emplotunneldrive excavation when Strathclyde Geotechnical Steel Division king based erative all-par d in due imposed e provid had a ea t in the Anderson fact representative on Grosvenor guidan Asses In using ct designer's and dama unders ed on city. course lead ty sea. in sments six Aquedu and ging effect by extens on inform Markham , predic tonthe convened PortaltheC instrum of all buildin under the mounted that Carsing Compensat servicein ation Solutions Team ted on the started at the so-called entatio ly meet French gs within of the 10.5km n and ive geotechnica Tunnelling ion grout the 12.4k 1mm settlem B and D in analysis. collapse to engineer m on did actual the UK and the shields. the ent conto 350m cross sections ing arrays m under l computer-b and at Portals immediately following the “The of dinal and Harris, ur along ground way forward. "The junction was within February 1982, at A in April. under ased a Direct aim,” explai and in economic Fig 2. Longitu route define the Westm a safe headings level. ned David stage, or of the by 900mm and finally the princip tunnel marine on March, s a inster area at an early company Clay below is supported the 60mm London d decided conditions, on comp al geotechnica installed which step in GCG as nts of It was line and create d ground diameterplan contiguous piles ensation l advise from five establishme side which a predicte r to of the 20m below, the grouting, tempo viewcliffs • The s on the UK comprehensive continue a further chalk andon, rary grout “is to keep JLE from, ng m3 e a excavati formulat capping beam at lagoon l headi the white ing shafts tomillion the method of Secant piles.

With "A substantial concrete collar e Tunne foot of ating the some 3.75 incorpor nt lining. at the a rigid UK Servic and tightly site for main forms and permane ground the surface e for the disposal what is an small roof support Employer, in all the 79piles together. manufactur linking nt of the were Report site. of muck TBM in in both the recovery ideas ies agreeme of CIRIA working s’ "Originally, Howden a large Practice endations high confined nt casting factorrecomm excavating of on Contract d based nds instinctively segme approach g - Improve Fig 1. Plan of the ‘Tunnellin nts were x 65m," said Powderham.

• The ries where thousa Gascoigne Wood and the general nts. 65m box of about y drifts and the five mine followed lining segme count shaft sites; UK factor contract documewere to tunnel Thewere tial in the Inset: Fig 2. Main ated precision at high rats. incorpor of the tunnel design features a poten day sections rock, the need for produced Grain had Although nt nts per 55 Isle of near segme on the driven in compete was expected d 4,42,7 of 1,152 requirebe roof support output immediate ced the and produ within 3.5 years. on of the 37 42 nts segme now goingand lengths installation units • The thousands of and other , track many al cabling of electric

REPORT

tax in the sewerage the water and served by rates for and cities the lowest clean 1997 one ofMAY 43 towns project to REPORT: had paid payers of VISIT ians SITE Boston ar, $6.1 billion when rate d water flowing to a ten-ye : For years in the 19080s t ted pollute contributed dramatically (MWRA) of the earlies that preven changed Authority was one programme USA. This r project Resources the TARP Milwaukee. tts Water Boston Harbo Harbor. After including Massachuse Lakes, the of Boston on since, pollution of the Great following fully assembled manyback-up Michigan up severe with Boretec and its Lake USA before EPBM the and into in go Mitsubishi behind ups the Pacific Ocean from Chica on clean shaft and site tested with t CSO polluti the 200ft deep access and larges being lowered into

CASE STUDY

CASE

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CASE STUDY:

Application of a TBM for developmen in North Yorkshire t of one of the was the first use twin spine roads of a TBM on a demonstrated to link five coal mining project the significant mines in the UK. The 5.8m advantages of Robbins went on diameter Robbins the technique to supply TBMs to over traditional mine CASE operations the roadheader excavation TBM non-circular TBM STUDYworld for excavating over. Most recently : Excava rectangular Robbins has developed and an estimat cross sections. tion of the ed half the first a new cost of creatin ever purpose built also provide LPG storage d greater g the same security for caverns in JUNE 1983 storage capac these vital the UK in CASE STUD ity in tanks infrastructure on the surface the 1980s were built facilities.

Y: JLE, the SITE VISIT turbulent at . Underground REPOR T: MARC London times. storage Excavatio including Undergrou H 1984 n the Big nd Jubile and Lond Ben clock progressed e on Bridg tower and under or along Line Extension services project, side to area e mainline railwa the Hous lived throu es of Parlia some of limits of s of south y statio the most the gh exciti ment; ns; and impo created excavatio Underground and east Lond ng as passed well as new metro rtant landm on, system. n work under arks of the most s colla Controlling which until the stations the city, pse he Selby coal critical unde excavatio then had rema River Thames labyrinth mine complex challenge on the conc of unlined in four times r the Waterloo Yorkshire was n and urrent s toget tunnels, driven designed by the settlement ined outside Heathrow ircuit and • Client: UK National her with SITEclosed-c UK National Coal the techn to bring metro in chalk VISI and loading Expre beneath Coal some mana Board mana Board (NCB) TS AND terminals 190m ical cons ss Rail the flatland to connect five ging the tankers for rail and ging the • Consultant: bank Link proje ABRatIDG separate mine sites on the south of the River truction National Coal budg Immingham. impact road - at Board Wistow, Stilling Fleet, Humber, ED FRO of the • Client:et and the M&E ct in October will be used first mined Riccall, Whitemoor as• the Contractor: M TWO Calor Gas Cementation 1994 were station and North Selby. underground Geology petroleum Ltd installation JLE SUPP Each would have liquefied gas (LPG) • Consult among s. a the UK. pair of shafts for The geology LEM ing Enginee storage transport

SITE VISIT REPORT:

UK F

1994 Rail Link in October the Heathrow Express prosecution excavations on world. The criminal of the NATM station UK and across the the works and CASE STUDY: Collapse s for the tunnelling industry in the later, after working on to recover during ramification ns made engineer four years had high impact shields and its design-buildnce of how decisio aders in the experie trial of the contractor to injury. insult a salient added that the roadhe than anticipated the project, uct was complete predicted aqued The more water Carsington for the project drill+blast. rock and 10.5km long ts mining or ctors bidding right when harder The hand amoun a Contra to turn ded CASE STUDY: seriously wrong. keep large and 1996 provi as. They were JUNE aders go ssed air to Its REPORT: roadhe in 1998, under compre cts. before Christm their es SITEtoVISIT design can upservic edproje giverail on the hillside advancre c was four drives would be against publi infrastructu ader shield, out of the ed to hmarks mega forced three dwhich kept its roadhe of future , stand as benc and open face, funding ingplete lems remain l, com . ion and ed prob control nizat under nel Tunne orga water document ofning, The Chan its well 1983 ative plan well as STUDY: T: MARCH CASE el for the innov successes, as VISIT REPOR the project in truction SITEkes.

• Client: BAA role mod mista that occurred on ng cons similar the mind, for the owner: job in the collapse will always focus outstandi s will avoid • Consulting Engineer hatever jinxed the well October 1994 achieved be to other h appears remains if it is being Mott MacDonald whic beginning, all of the question then? The

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