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GEOTECHNICAL APPLICATIONS Fillings in foundations, retaining walls, road embankments, quay extensions, drainages and insulation.


special edition: geotechnical applications TABLE OF CONTENTS 4 5 5 6 6 7 8 8 9 9 9

Introduction Geotechnical description Advantages Applications: Fillings in foundations and behind retaining walls Sub Base compensation Road embankment Quay extension Fillings of natural and artificial cavities Insulation of pipelines Tunnels and structural elements Drainage/Sport fields

Fillings in foundations and behind retaining walls 10 12 14 16

Amiens Büsum Town Council Gniezno Market Square


Sub base compensation 18 20

House foundation Bunratty bypass


Road embankment 22 24 26 28 30 32

Road embankment, Grimsby E18 Askim Skive Ådal bridge A new motorway in Sicily Island The quick line Load spreading Lightweight Slab


Grevelingendam Sønderborg


Quay extension 34 36

Fillings of natural and artificial cavities 38

“Grotte” at Caporciano


Insulation of pipelines 40

Trench Nesbukta


Tunnels and structural elements 41 42 44

Metrò Boadilla Tunnel Olympic Winter’s Games


Drainage and Sport fields 46 48 50

Arnestad Sport & Leca: a great team Research Park


Š Copyright by Leca International - Denmark - 2006 LECA Ž is a registered trademark owned by Leca Trading & Concession A/S - Denmark. Printed in Italy by Isabel Litografia, Gessate (MI). recycled paper

Introduction LECA ® (“Light Expanded Clay Aggregate”) is a ceramic lightweight aggregate produced by expanding selected clays in a rotary kiln at temperatures over 1.150°C. Certain clays have the property of expanding when they are heated to their melting point, because at this temperature certain chemical substances in the clay evolve gases. After the clay is treated and dry, it passes trough a kiln fired to a temperature of approximately 1.150°C. This process expands the pellets of clay to many times their original size. The resulting LECA® particle has a hard and resistant exterior skin and a cellular interior. These are the main features that give LECA® the optimum mix of lightness and resistance. The expanded clay pellets are then screened into their various fractions. The production and raw material selection processes are strictly controlled to ensure a uniform, high quality product that is structurally strong, stable, durable and inert, yet also lightweight and insulating. Today LECA® is used in masonry blocks, wall elements, premixed products for light and insulating screeds, lightweight geotecnical fills, roof insulation, lightweight and fire resistant mortar, hydro culture, and many other applications.

THE MAIN BENEFITS OF LECA® IN GEOTECHNICAL APPLICATIONS ARE: Low bulk density High insulation capacity Excellent drainage properties Non combustible Resistance to heat and frost Low capillarity Easy to spread and compact Large load bearing capacity Deformation resistance Inert and chemically neutral Resistant to fungus, rot, insect and pest Constant and high quality of the lightweight material Low transportation costs 4

Geotechnical description Grain size Light Expanded Clay Aggregate is produced in form of a round shaped brown pellets with a resistant exterior skin and a porous and lightweight interior nucleus. The optimum grain size distribution can be cut out in function of the specific application. The grading of LECA® for most geotechnical applications is 10-20 or 0-30 mm. Density LECA® loose dry density ranges between 250 and 450 Kg/m3 in function of the grain size distribution.

The dry loose bulk density of Leca is quite 1/4 of traditional natural sand.

Resistance Like all the other granular loose material, LECA® offers a frictional resistance without any cohesion. The internal friction angle is very high (40° standard triaxial test) and the stiffness measured on load plate test is exceptional for a lightweight material. Thermal conductivity The practical thermal conductivity may vary between 0,10 - 0,14 W/mK, depending on grain size, compaction, humidity level and type of technical solution. Durability LECA® is totally inert. It contains no harmful substances or gases and is absolutely neutral. Its resistance to chemicals is comparable to that of glazed tile or glass.

Advantages LECA® has been used as a geotechnical fill material in many European countries since as far as back as 1958. It possesses properties that can solve many problems simultaneously, providing simple solutions to a wealth of civil engineering challenges. Stability - reduced risk of landslide and deformation Reduced settlements - less damage to road structures, rail beds, pipelines and other structures Reduced earth pressure - in structural backfill against foundations, retaining walls and bridge abutments Drainage - on sports grounds, fields, slopes and roads Insulation - protection for roads surface, pipelines and service mains Frost stability - in road and rail beds Compaction - When properly compacted, the compaction degree will be approximately 10 - 12%. Low density and ease of handling, coupled with consistent high quality, make LECA® a highly competitive alternative to other lightweight materials.


Applications FILLINGS IN FOUNDATIONS AND BEHIND RETAINING WALLS (case stories at page 10 - 17) When used against retaining walls LECA will reduce the weight acting on the rear of the structure by at least 75%, in comparison to traditional fill materials. This reduction in weight avoids potential sliding, overturning, slip and tilting or bearing failures and enables savings by increasing spacing between buttressing walls and reducing structural dimensions. The bulk weight of the wall can also be reduced and more cost efficient, attractive materials can be used in place of costly, unattractive structural concrete. The use of LECA will also minimise the differential settlement between piled bridge abutments and the embankment fill. As it is a free draining material LECA, can also eliminate the need for rear wall block drainage. The 'pull out' resistance of LECA also makes it an ideal solution for reinforced soil retaining walls. Particularly when constructed over weak sub-soils or voids, this method can cut overall construction costs considerably.

SUB BASE COMPENSATION (case stories at page 18 - 21)

P= P1+P2


A loose lightweight material can grant high drainage capacity with a very low density. These features may solve problems in the filling of foundations on soft layers that could not support the whole building load. In case of soils with low bearing capacity, that will have non acceptable settlements, it's possible to realize the foundation with LECA. The load compensation method consists in the substitution of a natural soil mass with an equivalent Leca thickness so that the new load of LECA foundations plus the whole building load doesn't exceed the natural soil load that has been removed.

ROAD EMBANKMENT (case stories at page 22 - 33) LECA's ability to reduce settlement can offer massive benefits, reducing timescales from years to a few months for new or extended carriageways or for embankments and even, in some instances, eliminate settlement periods altogether. Construction of embankments over weak and compressible soil deposits, where the loading of the embankment causes soil consolidation and settlement, is common. Depending on the height of the embankment, the depth of the weak soil deposit and the consolidation properties of the soil strata, total settlements can be very deep and problematic in terms of road evenness, function and durability of the road construction. In the most difficult cases, various combinations of soil strengthening techniques are available, for example, pre-loading, vertical drainage and deep stabilization with piles - all of whick are time consuming and costly to install. By lightening the embankment with LECA lightweight aggregate, subsoil strengthening and lengthy settlement can be reduced or even avoided altogether. In present figures some different ways to realize lightweight road embankments are represented: without load compensation (A and B) and with compensation (C and D). In the first two cases the lower LECA density represents a lower distributed load on the weak foundation soil. In the other two cases a natural soil stratum is substituted with a calculated quantity of LECA that will have the same load on the foundation layer but approximately four times the volume. LECA will also reduce the risk of bearing capacity failure and increase the stability of the side slopes. Efficient drainage of the structural layers of the road build-up can prevent loss of load bearing properties caused by water and ensure a good load bearing capacity throughout the road life. Using free draining LECA within the road build-up will break the capillary rise of ground water into the upper construction layers whilst performing as a structural material and improving the load bearing capacity. In sloping terrain and in cuts stretching below the surface of the ground water, streams of groundwater can cause localised damage to the road surface and reduce the load bearing capacity of the road. LECA used as a drainage layer within the road construction will intercept the perco-





lating water and water rising by capillary action from the sub-formations and direct the rising water within carriageways in cuts that extend below the natural level of the groundwater, frost damage and loss of load bearing capacity can also be reduced by forming drain trenches filled with LECA at both sides of the road, along which the water is led away Used within the carriageway drainage, LECA helps filter and increase microbiological breakdown of pollutant runoff from fields and highways.


QUAY EXTENSION (case stories at page 34 - 37) When constructing quays, the soft ground conditions often call for the use of lighter fills to guard against slides or deformation that can damage structures and a number of solid berth structures have been built in recent years using LECA. It can be used to an advantage in many quay designs such as sheet pile, sheet pile cell and caisson structures and is also used as fill replacement in solid berth structures when quayside waters are dredged to greater depths. LECA not only has a very low unit weight, it also has minimal buoyancy, making it particularly suitable for filling directly into water. By depositing the aggregate directly into place from a boat equipped with its own offloading gear, exceptionally fast progress can be made with 250-300 cubic meters per hour quite achievable.

FILLINGS OF NATURAL AND ARTIFICIAL CAVITIES (case stories at page 38 - 39) The filling of underground cavities with loose aggregates attempts to restore the subsoil situation as it was before. The presence of a hole into the ground may concentrate traction and compressive strain that can conclude with the general collapse of the structure. Using LECA (loose or mixed with cement) can avoid the concentration of the strains thanks to his high grain resistance that can redistribute the force diagram. The advantage is more evident if there is the suspect of a multi level system of cavities with some of them not even being possible to be reached. In these cases the LECA solution may be the only one or in fact the most safe. By pumping high quantities of LECA per day, it is possible to obtain a complete filling of the cavity with high drainage capacity, good resistance and a stiffness similar to that of the natural original ground.


INSULATION OF PIPELINES (case stories at page 40) Maintaining levels within any foul or surface water drainage system can be difficult when the drain runs across a soft soil site. LECA can be used as a lightweight pipe surround, reducing the pressure to the underlying soils and minimising the likelihood of irregular settlement. Surrounding utilities and drainage carried within bridge beams either side of the carriageway with LECA is a lightweight, simple to install alternative to that of sand traditionally used to support and

insulate these services. The added benefit of using the lightweight round granules of LECA as a pipe surround is that there is little danger of any damage to pipelines during backfilling and the likelihood of damage from settlement is also reduced.

TUNNELS AND STRUCTURAL ELEMENTS (case stories at page 41 - 45) In areas prone to mining subsidence or where ground conditions contain natural sub formation voids, drainage, culvert or tunnels and there is a danger of collapse, expensive techniques such as load transfer are often considered. However, using LECA can eliminate these costs and considerably lighten the load to provide similar benefits to those when used in weak soil areas. In particular, during the construction of tunnels, unexpected voids and small cavities around the concrete may collapse on the structure. Lightweight filling with the use of loose or cemented bound LECA can be archived with very low costs of handling thanks to the pumping opportunity.

DRAINAGE/SPORT FIELDS (case stories at page 46 - 51) Environmental compatibility, high permeability and total drainage capacity, make Leca the optimum aggregate to realize perfect draining layers over concrete structures, sky garden and sport fields. The LECA thikness protects the structure and the rain proof materials from severe thermal range, recreates an optimum habitat for green vegetation and offers a long reserve of water and air for plants and grass. Different layers of LECA, geotextile and natural soil may realize a good and durable cover green system.


Fillings in foundations and behind retaining walls


In March 2004 the reconstruction of the national road RD 929 between Amiens and Albert was carried out in Amiens (France). The objective was, indeed, to reduce as much as possible the traffic nuisance in the rural municipalities Querrieu, Pont Noyelle and Lahoussoye by means of a diversion. The result of this intervention was, among others, that the heavy lorry traffic would be diverted from now on. The reconstruction also included the construction of a viaduct on pile foundations over the river l'Hallue. On the subsoil, a thick bed of compressible peat was laid. In order to reduce the settlements to a minimum, the west side of the viaduct was filled up with Leca aggregates. After removing the pre-load, carrying out the earthworks, ramming the piles and constructing the bridge head, the Leca aggregates were laid over a total length of 35 m, a height of 2 m and over the total width of the platform. 850 m3 in total. A geotextile layer separates the clay aggregates from the other filling materials. On top of it, a classic sand coffer 25 to 30 cm thick was poured. „


FRANCE TECHNICAL DATE OF THE PROJECT Total volume: 850 m3 Grain size: 8-16 Period: March 2004 Place: Amiens (France) Client: Municipal Council of Somme, DDE (Somme) and the French Road Construction Company (Grands Travaux Routiers) Contractor: Baudin Chateauneuf, BRON (Lyon) Consultants: COGECI (Vaulx en Velin)


Fillings in foundations and behind retaining walls

Büsum Town Council EMBANKMENT SLOPE/STREET RESTRUCTURING - 2004 The new construction and alterations to the front square brought additional loads to bear on the surrounding soil as a result of filling and additional layers. In order to reduce soil pressure and minimise settling, 8-16 mmsize GEOTON was used. The job owner, Büsum town council, in consultation with the Bornholdt engineering bureau from Albersdorf, selected expanded clay (GEOTON 8-16 mm) as light aggregate for the embankment structure and foundation fill. The construction project is situated immediately next to a protective embankment. New construction work is taking place alongside extension and reconstruction work using pillars on the existing wave pool. The foundation and embankment fill must attain a total height of between 2m and around 5m. As the new work is to be incorporated into the protective embankment, in consultation with the ALR (Amt für Ländliche Raum, Hüsum), special measures are to be taken to ensure the stability of the GEOTON light aggregate. This has given rise to a new construction method, allowing GEOTON light aggregate to be applied in costal defence zones. The terrain is made up of coastal marsh layers (shale, peat), which are subject to settling. Following tree challenges had to be taken into account, in the very odd soil conditions and landscape: dimensional stability; filtration stability; slope stability.


To ensure all the above dimensional characteristics, loose LWA was chosen in combination with geotextile and a cement binder. Due to the low specific weight of the expanded clay fill (1/3 of the specific weight of a conventional fill), any settling of the subsoil in response to the load is minimised and the soil pressure on the lateral walls is reduced. Filtration stability between the conventional fill material (sand, sand/gravel layers or sand/gravel mix) and the 8-16 mm-size expanded clay fill was achieved by using a geotextile. The surface of the expanded clay fill was, in some areas, sprayed with cement slurry, to strengthen the surface. The slurry was delivered at site in silos and pumped into the different working area to speed up the application. „

GERMANY TECHNICAL DATE OF THE PROJECT Designer: Ing.-Büro Bornhold, Albersdorf Ing.-Büro Lehners + Wittorf, Lübeck Contractor: Kähler Bau GmbH, Büsum Place of job: Büsum Town Council Street restructuring - Germany Date of application: 2004 Quantity of Leca: 1.000 m3 Type of material: 8-16mm Others Geotextile: 1500 m2 Geolon PP 40L GEOTON - Binder: 7 Ton cement slurry


Fillings in foundations and behind retaining walls

Gniezno ROAD DEFORMATION AND SUPPORTING WALL GNIEZNO, POLAND - 1997 POLAND TECHNICAL DATE OF THE PROJECT Design: Technical University in Poznan, Doctor Civil Engineer Jerzy Rzezniczak & Doctor Civil Engineer Slawomir Janinski Investor: GDDKiA Poznan (General Directory of Country Roads and Motorways, Poznan) Contractor: MOSTY Plock Oddzial Paznan (BRIDGES Plock in Poznan) Place of job: Country Road N° 5 in Poland in Gniezno - Poland Date of application: 1997 Quantity: ca. 7.000m3 Type of material: Leca 10-20 mm


Repair a deformed old road - country road N° 5, and secure future deformations against a lake. The road had severe deformation, due to soft soil and its location close to a lake. Reduction of loads with 2,4 m layer of LECA placed in a geotextile, covered with 0,70 m of crashed stone, reinforced with a polyester mesh. Approx. 120 m of the road is passing near by Winiarskiego Lake. The clay “ceiling” layer has 28-degree downtrend to the lake. Static (load from the road) preliminary was secured by building supporting concrete wall 22 high (depth). Below the road is mad so they supported the road with pales build from crushed stones. The road and wall was built in 1997. After few years, under the traffic load, appeared vertical deformations of the road as (see the photo) as well 14 cm horizontal deformation (direction to the lake) of supporting wall. „


Market square BELGIUM TECHNICAL DATE OF THE PROJECT Place: town centre Mechelen Period: 2003 - 2004 Contractor: DCA (Beerse) Consultant: Giluco Principal: city of Mechelen Volume: 6.000 m3 Aggregates size: Leca 8-16

LIGHT FILLING ABOVE UNDERGROUND PARKING MECHELEN, BELGIUM - 2004 In 2003, the city of Mechelen decided to renovate the centre of the city. At the end of 2003 - early 2004, the Grote Markt and the Veemarkt were equipped with an underground parking. The city seized the opportunity of the renovation to waterproof the inner court of the city hall, where the archives are kept in an old cellar. Since an underground parking was involved, the filling material had to be limited in weight. In addition, it was important to choose a material with good draining capacities. Keeping these conditions in mind, it was decided to use Leca. Leca 8-16 aggregates were laid in two layers. Pipes, needed to drain the water of the parking roof, were laid in a first layer of loose Leca aggregates. On this layer, a second layer with cement-bound Leca was poured. This layer was needed to bring more stability in order to support the sand and cobble stones. In addition, these locations are regularly used as a meeting point for commercial and recreational activities, such as the weekly markets, annual fancy-fairs and a rock festival in summer. Therefore, the built-up construction required sufficient bearing strength to support these huge weights. The total thickness of the Leca layer varies between 30 and 60 cm. „

Fillings in foundations and behind retaining walls



Sub base compensation

House foundation LIGHTWEIGHT HOUSE FOUNDATION FREDERIKSHAVN, DENMARK - 2004 DENMARK TECHNICAL DATE OF THE PROJECT 1.400 m3 Leca installed Year of construction: 2004 Consulting Engineers: NIRAS A/S designed the geotechnical solution. Contractor: Bangsminde ApS in Frederikshavn.


The city of Frederikshavn is building housings. The construction side is soft soil. The soft soil is located very deep and it is therefore not accessible for replacement by normal weight gravel. Pile foundation was another possibility but was considered less applicable. Both the methods replacement with normal weight gravel and pile foundation was calculated to be more expensive than load compensation. Load compensation with Leca was therefore the solution to the problems. The density of the used Leca is only one sixth of the removed soil. A 90 cm soil stratum was removed and replaced with Leca. This replacement was enough to carry the buildings and to ensure that no settings will occur. The house foundation is pre-fabricated concrete elements placed directly on the Leca light filling. After that the Leca floor insulation was installed in between the elements. The concrete floors were then cast together with the pre-fabricated foundation elements. The concrete floors were reinforced with normal steel reinforcement to form a solid load distribution platform witch also gave the basis for the floor construction. This gives stable and well-insulated base for the erection of the house. The construction method was very fast and even though the houses were erected in February with temperatures below the freezing point there were no problems. The houses are traditional double leaf walls with a clay brick facade. 12 houses were erected on the Leca light filling. „



Bunratty bypass Sub base compensation


IRELAND TECHNICAL DATE OF THE PROJECT Contractor: Clare County Council / National Roads Authority (NRA) Place of job: Bunratty - Ireland Date of application: June 2005 Quantity: 6.000 m3 Type of material: Leca10-20 mm Time table: 17/06/05 - 25/07/05

The N18 was constructed 15 years ago over soft sub-soils which are now thought to be where the local river used to flow. The west bound section of the dual carriageway has settled quite substantially within 5 areas along the stretch adjacent to Bunratty Castle. Leca 10-20 mm was used to replace the heavy road construction materials originally used to the underside of sub-base. Leca 10-20 mm was delivered by a 5.000m 3 capacity ship directly into the port of Foynes, not far from the site and then transported over a period of 2 days in 60m3 high sided artic tipper vehicles and loose tipped into a storage bund local to site. Whilst the repairs were taking place, the west bound N18 traffic was temporarily moved onto the east bound carriageway reducing the N18 into a single carriageway. For this reason, time was limited and speed of installation was essential. Once Clare CC had excavated the first of the 5 areas that needed to be re-levelled, the Leca was transported from the storage bund and tipped directly into the void. The Leca was then compacted using a 360 degree excavator in 1 metre layers, the same equipment that was being used to distribute and level the Leca across the subformation. The use of Leca 10-20 mm provided a simple lightweight repair solution to the existing carriageway. The design was expected to achieve a minimum 20 year design life. The installation was very quick and simple and the contractor, Clare CC works department were happy with the speed in which they were able to carry out the works and re-open the busy N18 to traffic. „


Road embankment




Phase 2 of the West Marsh Renaissance scheme in Grimsby. The whole scheme which will consist of phases 1 - 3 will form part of the infrastructure to a proposed new retail and leisure park and a new housing scheme. The land is currently owned and being developed by P&O. Phase 2 consists solely of a new integral bridge that will allow access into the new development over an existing railway track off Cromwell Road. The existing ground conditions either side of the rail track are extremely boggy, particularly on the north side were the ground forms part of an old land fill. Excessive loads adjacent to the track need to be avoided to eliminate the possibility of heave and distortion to the track. Leca has been designed as bulk fill within the approach embankments to the bridge - 20,000 m3 to the south and 25,000 m3 to the north. Leca is being used as the most cost effective solution to this scheme due to the considerable weight reduction when compared to that of general fill. Due to the increased depth of compaction layers and the increase in haulage capacity when compared to general fill, the main contractor, Norwest Holst also found a considerable reduction in programme time for installation proving another considerable cost saving. 9 x 5000 m3 capacity ships discharged LWA directly into stockpiles at Grimsby dock ready for call off from site in Grimsby, 5 minutes journey by wagon. The LWA 10-20 mm was delivered in bulk to site in 50 m3 capacity articulated tippers and tipped directly into the void. Tracked excavators and dozers moved the material into position, then tracked and compacted with 3 - 4 passes of the same vehicle. Installation is extremely quick and easy by nature of the material together with large compaction layers. The LWA embankment was wrapped with a geotextile to prevent migration of fines from the capping material as the embankment is constructed. „

TECHNICAL DATE OF THE PROJECT Designer: White Young Green Contractor: Norwest Holst Place of project: UK - Grimsby Time table: October ‘05 - January ‘06 Quantity: 45.000m3 Type of material: Leca 10-20 mm


Road embankment


Motorway project on E18 in Askim is consisting of two separate Leca fillings, one of them against abutments of a bridge in combination with EPS. The problem was ground consisting of soft clay with potential to settlements. Leca was used to compensate the additional load of the embankment on the subgrade and to reduce the settlement variation in the fill behind the abutment. After removal of the topsoil and excavation to required level, a geotextile was laid out on the ground. The Leca was brought in by lorries and tipped directly into the pit. Layers of Leca around 1 m was spread out and compacted with tracked bulldozer. Maximum thickness of the Leca fillings were 4 m. „


TECHNICAL DATE OF THE PROJECT Designer: Norconsult as Contractor: HĂŚhre as Place of job: E18 SekkelstenKrosby in Askim Period of job: 2004 Volume: 52.000 m3 Type of material: Leca 0-32 mm


The longest road bridge over ground in Denmark is situated in the Skive Ådal stream valley. The 441 m long bridge is part of a connecting road south of the town of Skive and is constructed in a typical soft soil area. Two 10 m high embankments form the connection to the bridge. The core of the embankments consists of compressed lightweight aggregate - a solution that, in addition to being economical and easy to work with, reduces differential settings between bridge and embankments to an absolute minimum. The problem for the Danish Road Directorate and the consultants in connection with the Skive Ådal embankments was to limit the pressure of the 10 m high constructions on the soft valley soil and thus minimize the risk of settings in places where the bridge itself and the embankment met. By using Leca lightweight aggregate as filling as opposed to traditional soil or sand filling, a considerably smaller pressure was achieved - approx. 2 tons less per m3 and an effective reduction of the differential settings. Experience shows that roads with lightweight aggregate as lightweight fill will settle max. 1-2 cm, even several years after opening. The core of the two embankments is constructed of a total of 13.000 m3 of lightweight filling based on 0-32 mm lightweight aggregate with an average dry density of 300 kg/m3. The lightweight aggregate is applied in layer thicknesses of 75 cm and in order to avoid mixing of materials, the lightweight aggregate is “wrapped” in a fibre cover with a 50 cm overlap at the joints. The lightweight filling core is covered with a supporting layer of earth fill. This provides a both stable and simple solution to the geotechnical problem faced by this project. „

Road embankment


DENMARK TECHNICAL DATE OF THE PROJECT Designer: Geoteknisk Institut Contractor: Højgaard & Schultz Place of job: Skive Ådal, Denmark Period of job: 1995 Volume: 13.000 m3 Type of material: Leca 0-32 mm Others: Denmark's longest road bridge over ground. 441 m long bridge



Road embankment

A new motorway in Sicily Island LECA REINFORCED LIGHT EMBANKMENT TORREMUZZA, ITALY - 2003 ITALY TECHNICAL DATE OF THE PROJECT Buyer: Consorzio Autostrade Siciliane Designer: Technital spa - Verona Contractor: Bonatti spa Lot number: 27 bis Period of job: 2003 Volume: 12.000 m3 Type of material: Leca 0-30 Contractor: I.N.C. General Contractor Lot number: 27 Period of job: 2003 Volume: 9.000 m3 Type of material: Leca 0-30


The main highway of Sicily, the widest island situated in the southern part of Italy, is coming up to be terminated. The alignment of this road of more than 250 Km that will connect the cities of Messina and Palermo crosses an important slope involved in landslide dangerous movements. The previous building construction road systems have failed because unacceptable settlement level of the road level had been reached at the term of the work. Leca lightweight road embankment have been chosen to realize three high earth step to reach the final level of about 11 meters. The reinforcement system is the “terra armata”: some concrete pre-cast elements realize the external lateral containing system while some iron bars inside the Leca filling receive the share forces. To maximize the stiffness of the Leca layers a strong activity of compaction has been involved so to reach high values measured with the load plate test. At the end of the job the values of differential settlements were absolutely comparable with the required design prescriptions. „


Road embankment


FINLAND TECHNICAL DATE OF THE PROJECT Client: The Finnish State Railways Planner: The National Finnish Road Administration The Finnish Road Administration Consultant: Unit Southern Finland Contractor: Kes채lahden Maansiirto Oy (an earthmoving company) Consultant to the client: Lemcon Oy


The quick rail line between the towns of Kerava and Lahti measures 74 km in total of which the new section has a length of 63 km. The route of the quick line is practically parallel to the Lahti motorway. The building contract for the railway line was split into ten land construction subcontracts and 11 bridge construction subcontracts. Totally 15,000 cu.m. of Leca gravel was used at several junctures of the project, i.e. to make the railway embankment lighter, under pile slabs as well as in road and bridge constructions. Approx. one km of the section is previous arable land which stretches to Hakosilta village in Hollola, just before the rail junction leading from Riihim채ki to Lahti. The height of the area is +82 to + 83 metres. Hard bottom lies deep beneath the surface of the ground, at a depth of 45 metres on average. The soil in the area contains clay and silt with a shear strength in the range of 15-30 kPa and a water content between 50% and 90%. The construction techniques used for the MRU3 project covering the section between Luhtikyl채 and Hakosilta were chosen after technical and financial analyses had been made. If piling foundations had been used, the piles should have been of extraordinary length due to soft soil of a substantial depth. Part of the section has a rock surface which is extremely sloping. This would have required the use of expensive drilled piles. Foundation reinforcement was carried out on a distance of 1,000 metres by using deep stabilisation and by applying a layer of Leca gravel to make the embankment lighter. By depositing a layer of Leca gravel on the track embankment the subsidence of the embankment is minimised, subsidence of the lateral section is prevented, and stabilisation reliability is increased. The vibrations caused by high-speed trains have been taken into account in the construction planning. To determine vibrations, laboratory analyses of the local clay, of stabilised test samples and of the surface wave speed of light-weight gravel were made. The results show that light-weight gravel does not increase the dynamic strength of the track embankment, because the surface wave speed of light-weight gravel is much higher than the train speed. The lime cement columns used for deep stabilisation have a diameter of 700 mm with a planned shear strength of 150 kPa. The total length of the columns is 56,700 metres. A layer of Leca gravel is placed between the two parallel embankments at the bottom of the construction. Reinforced geotextile surrounds the Leca gravel. In the deep stabilised section a geotextile of polypropylene (PP) is used to ensure chemical resistance. There is one metre of overlapping geotextile at the middle of the embankment. The theoretical volume of Leca gravel needed in the section between Luhtikyl채 and Hakosilta is 9,200 cu.m. By using this technique a cost saving of approx. 1.6 million euros has been achieved in comparison to piling foundations. The stabilising columns were allowed to harden two weeks before the embankment was constructed. A layer of light-weight gravel was deposited between the edge embankments which were made from crushed stone. The Leca gravel was transported by lorries equipped with full-length trailers whose maximum transportation capacity is 135 cu.m.

A one metre thick layer of gravel was laid on the reinforced geotextile spread between the edge embankments. The geotextile was folded to form an overlapping part of one metre over the Leca gravel. A layer of crushed stone measuring 0.3 metres in height was placed on top of the geotextile. The embankment was compacted by running a vibrating drum roller with a weight of 5 tonnes six times over the surface, in accordance with the instructions issued by the Finnish State Railways. Construction proceeded without major difficulties and according to schedule. „


Road embankment

Load spreading Lightweight Slab BROADENING AND ADJUSTMENT OF NATIONAL HIGHWAY GÖTEBORG, SWEDEN - 2005 SWEDEN TECHNICAL DATE OF THE PROJECT Designer: Vägverket Konsult Contractor: Älmby Väst Place of job: Göteborg - Sweden Date of application: Summer of 2005 Quantity: ca. 8.000 m3 Type of material: Leca 8-20 mm Time table: 2005/06 - 2005/09


In connection to adding one lane to the E6 highway, the problems with consolidation settlements in the underlying clay had to be taken care of and the road profile adjusted. Geotechnical reinforcements to avoid further settlements or differential settlements had to be considered. Load compensation with Leca and LLS. For the LLS the Leca was loaded from silo into cement trucks with a rotating cylinder volume of about 7,5 m3. Then Slurry was added at a concrete plant and the material mixed on the way to the construction site. „


Quay extension

Grevelingendam LIGHT FILLING BEHIND QUAY WALL GREVELINGENDAM, NETHERLANDS - 2004 NETHERLANDS TECHNICAL DATE OF THE PROJECT Type of aggregate: Leca 8-16 Volume: 3.500 m3 Period: 2004 - 2005 Place: Bruinisse (Netherlands) Principal: Rijkswaterstaat (Province of Zeeland) Main contractor: Hakkers BV (Werkendam)


The Province of Zeeland, Rijkswaterstaat (Ministry of Waterways and Public Works) and contractors realized the completion of a bypass with a rolling bride over the Grevelingen dock near Bruinisse (the Netherlands) for the road traffic on the National Road N59 to Schouwen-Duiveland. For many years, the crossing of road and shipping traffic at the Grevelingen lock near Bruinisse has caused long tailbacks and unsafe conditions in the summer, both on the road as well as on the water. On summer peak days, well over 20.000 vehicles use the N59 while at the same time hundreds of pleasure yachts pass the lock every day. For sailing in or out, the bridge is open for about 15 minutes at a time. With the completion of the bypass and the second bridge over the lock, the road and shipping traffic can pass non-stop independently of one another. The bridge that is built in addition is a “rolling bridge” meaning that it is on wheels and can move back and forth. It was the first time this type of bridge was used on such a large scale. The bridge consists of a steel bridge section of 265 tons, which spans the lock, and another steel-concrete bridge section, which is at the back, and weighs about 400 tons. The great advantage of this rolling bridge is that it does not stick out above the ground level. This way, it is not noted in the landscape and is perfectly integrated in the environment. There is little work for the bridge master too: one push on the button and the whole system starts. The bridge is opened or successively closed with the same button. The electric motors only need 120 seconds, or 2 minutes, to complete the whole cycle. Leca aggregates (8-16) are incorporated on two spots in the work: on the one side, the northern part of the site, as light filling behind the concrete land abutment; on the other side, the southern part, as filling for the steel dam wall under the concrete land abutment. Leca aggregates, with a total volume of about 3.500 m3, were shipped in by barge. Subsequently, they were transported to the site by truck. There, they were poured into the work and moulded by means of cranes. The geotextile was closed, and sand was poured over it. The light weight of the Leca aggregates was chosen since they bring little pressure to bear on the steel and concrete walls. In both cases, sand would develop a too strong force on the walls. At the end of June 2005, minister Karla Peijs of Traffic and Waterways and a member of the Provincial Executive, Toine Poppelaars, of Zeeland have officially opened the second bridge over the Grevelingen lock at Bruinisse. „


Quay extension


DENMARK TECHNICAL DATE OF THE PROJECT 700 m3 LECA was installed. Date of application: 2000. The client was the municipal of Sønderborg. Consulting Engineers Rambøll in Sønderborg designed the geotechnical solution. Contractor was NCC A/S in Sønderborg.


Sønderborg are situated in the south eastern corner of Jutland close to the German boarder. Als is Denmark's 7th largest island and is connected to the mainland by two bridges in Sønderborg. Als Sound slices the town in half and separates Jutland from Als. Sønderborg are grown around the fortress built in the 11-1200s and the city celebrates its 750 anniversary in 2006. The quayside road, Havnegade, in Sønderborg Harbour needed to be renewed. Traffic load on the road has increased and the road needed to be renovated. The old quarry run was removed and a new quay construction was established. The old bulkhead was exchanged with new steel sheet piling and a new pine deal bulkhead. To reduce the pressure on the harbour bottom and the new steel sheet piling Leca light filling 10 - 20 mm was installed. Calculations showed that installation of normal weight gravel would give unacceptable settings of the quayside road. On top of the Leca light filling layer the quay road construction was established. „


Fillings of natural and artificial cavities

“Grotte” at Caporciano FILLING OF NATURAL CAVITIES CAPORCIANO, ITALY - 1990 ITALY TECHNICAL DATE OF THE PROJECT Date of application: 1990. Designer: Rodolfo Giacco, engineer. Contractor: Fondedile, Napoli.


In the small town of Caporciano, in the central part of Italy, the natural composition of the underground soft rock gave place to a lot of artificial cavities excavated during the time by the population to obtain material and cattle storage. As these cavities became more and bigger, some settlements problems begun to happen particularly in those zones in which the underground holes were more superficial and near to the buildings' foundations. The local authority decided to start a renovation plan to fill the cavities and avoid dangerous collapse events and save the integrity of building and pipeline systems. After the underground survey with experimental and geo-radar analysis, was decided to fill the superficial stratum of cavities with Leca that was demonstrated to be the only material with low density and sufficient grain resistance to support the final load. In some cases has been installed a mixture of Leca and cement to increase the stiffness. Another big problem was that many of the cavities were very hardly reached by the normal machines and trucks. For this reason lot of quantities of Leca were pumped directly into holes of small dimensions but with lot of cubic meter of void. „


Insulation of pipelines


NORWAY TECHNICAL DATE OF THE PROJECT Designer: Fjellanger Widerøe as Contractor: Valdres Anlegg as Place of job: Nesbukta in Asker Period of job: 2002 Volume: 800 m3 Type of material: Leca 10-20

300 m section with Leca as insulation of a new pipeline in shallow trench. A renovation of a local road placed over the pipeline also include this project. The problem was feasibility of a trench to frost free depth in soft soils and clay. With a shallow system the trench depth was reduced with about 50 % of normal excavation depth. This simplifies the excavation and problems with slope stability and ground water level . The trench was excavated to desired depth at about 1,20 m, and a geotextile was laid out on the bottom and covered up along the slopes. An adjustment of the bottom with crushed fine fraction of rock was carried out before the pipelines was laying out. After this the Leca was blown directly into the trench up to a level about 0,3 m over the top of the pipeline. The geotextile was now laid out over the top of the Leca and crushed rock and gravel for the sub base of the local road was installed. „


Tunnels and structural elements


SPAIN TECHNICAL DATE OF THE PROJECT Contractor: FCC Place of job: Spain - Madrid Date of application: 1999 Quantity: 4.000 m3 Type of material: Leca 8-16 mm (dry density of 350 Âą 50 kg/m3) Time table: 3 days

La Ventilla Subway station is and old station that has been used from a lot of years ago with out problems. This area of the city 7 years ago started to be changed and a new avenue was going to cross the station This old station was no calculated to a new cover of 2 metres of soil because was necessary elevate the level of the street. The first possible solution was to reinforce the concrete structure. This solution was too expensive, difficult and very slow. Finally the best solution was a light weight filling with Leca that made possible not to reinforce the station. In 3 days a very important and expensive problem was solved with a filling of 4.000 m3 of Leca. „


Tunnels and structural elements


SPAIN TECHNICAL DATE OF THE PROJECT Designer: ALEPH Consultores Contractor: Radiales UTE (ACS, FCC, OHL y SACYR) Place of job: Spain - Madrid - M50 Date of application: 2004 Quantity: 100.000 m3 Type of material: Arlita 0-30 mm (dry density of 350 ± 50 kg/m3) Time table: from January 2004 till June 2004 Others: Max thickness = 5,80m


Madrid is immersed in a big infrastructure project to get better its access and internal transport. The big grown of its population, and the increase of traffic, have produced the necessity of the construction of a third ring road to Madrid, 25 kilometers from the center, besides radial motorways to make easier the access to the city. In the section of M-50, that goes from A-5 to A-6 motorways was necessary the construction of a false tunnel, 500 m long and 19 m diameter. After the concrete frame of the false tunnel was finished, and starting the filling with soil, important structural troubles were detected because of using a wrong construction process. With these proceeding, and being necessary the reconstruction of the tunnel at the same time that the traffic was going to begin, it was essential the use of a light expanded clay filling of Arlita, that allowed solving the trouble by lightness, fast installation and easy handling. Supply of Arlita was transported principally with 80 m3 dumping trucks that allowed spreading Arlita more than 3.200 m3 per day. Spreading and compaction made with 2 bulldozers, by using layers of 1 m and 4-5 passes, permits an easy, fast and efficient work. When the Arlita filling will finish, a soil layer and an organic soil layer will spread to replant the woodland. „

LECA 0-30


Tunnels and structural elements


ITALY TECHNICAL DATE OF THE PROJECT Designer: C.A.V. TO-MI Contractor: Impregilo Place of job: Italy - Rondissone Date of application: 2004 - 2005 Quantity: 17.000 m3 Type of material: Leca 8-20


The national government plan for the highways and railways building plan has programmed an intense building activity to connect the main Italian cities. In the northern part of Italy one of the most important railway route is that one from Milan to Turin. During the years from 2003 to 2006 the whole railway has to be finished before the beginning of the 2006 Olympic Winter Games in Turin. Near the small town of Rondissone the railway road design goes underground in a false tunnel. The superior earth layer thickness varies from 1 to 5/6 meters. The definite project prescribes to fill the false tunnel till the final natural level with Leca 8-20. A total amount of 17.000 m3 of Leca has been pumped with more than 300 cisterns in less than 6 months because no heavy truck could reach the job work. Using Leca means to remain low with the density, grant a constant drainage system, and offer a sufficient resistant sub-layer to the final green cover. „



LECA 4-10


Drainage and Sport fields

Arnestad ARNESTAD FOOTBALL GROUND ASKER, NORWAY - 2005 NORWAY TECHNICAL DATE OF THE PROJECT Designer: Ing. Kenneth Kennedy Berg Contractor: Isachsen & Løvaas as Place of job: Arnestad, Vollen in Asker Period of job: 2005 Volume: 2500 m3 Type of material: Leca 0-32 mm

An existing football field was renovated to a modern artificial grass field with Leca as frost protection and drain layer The ground consist of marsh and soft soil with silt which can cause problems with drain and settlements Leca was layed out as a frost protection and drain layer under the top layer to give stable condition. The soil layer on the existing field was removed and a geotextile was laid out. Then Leca was spread out with bulldozer in 0,28 m thick layer and covered with a new geotextile. Over this a 0,20 m thick layer of crushed rock of fraction 4-63 mm was levelled and compacted. A finer fraction of 0-8 mm in a thickness of 2-3 cm is the finish layer under the artificial grass. „


In comparison with other filling materials, Leca aggregates are very light, resulting in an enormous weight saving, thus reducing the chances of subsidence to a minimum. A Leca layer also has a very good draining capacity, thus draining off the excess of water at a high pace, preventing inconveniences at the same time. With this, Leca has found a new field of application, contributing to lots of sports fun. An example of such a work is the artificial sports field in Oudekerk a/d Ijsel (see photo). Isa Spor t, the Dutch Institute for Spor ts Accommodation, has made a research, at request of Leca, on the suitability of crushed clay aggregates (Leca 0-4 ) and uncrushed clay aggregates (Leca 4-10 ) in a substructure construction for sports fields. Earlier, the suitability of crushed clay grain for substructure material was already investigated on the basis of the standard ISA-M34.a (March 2004). These results could be taken over and checked against the standards for a substructure construction. Since the clay aggregates are crush-sensitive, in addition to the previous research, a number of extra qualities were investigated: stability (static and dynamic), porosity and water absorption after crushing. Each time, the tests gave positive results. Therefore, Isa Sport came to the conclusion that a substructure construction composed of a layer of crushed clay aggregates (Leca 0-4 ) of 70 mm on a layer of uncrushed clay aggregates (Leca 410 ) of 120 mm and enveloped by a geotextile, is suitable for application in sports constructions. A copy of this research report can be obtained on request. „


Drainage and Sport fields

Sport & Leca: a great team LIGHTWEIGHT FOUNDATION OF FOOTBALL FIELD OUDEKERK, NETHERLANDS - 2004 NETHERLANDS TECHNICAL DATE OF THE PROJECT Period: spring 2004 Chief contractor and supervisor: Noteboom (BAM) Leca volume: 3.400 m3 Type of Leca: 0-4 crushed (1.600 m3), 4-10 round (1.800 m3) Place: Oudekerk a/d IJsel


Drainage and Sport fields


BELGIUM TECHNICAL DATE OF THE PROJECT Place: Leuven, “Arenberg” Period: 2005 Principal: Interleuven Contractor: Aqua Space Volume: 1500 m3 Type of aggregate: Leca Argidrain 8-16 mm


The department “public works” of the local authority in Leuven is momentarily working at the development of the research park “Arenberg”, a prestigious site of approximately 11.5 ha situated along the Koning Boudewijnlaan in Heverlee. Large areas have been built on this site for offices, laboratories, etc. Also, provisions are made for a comprehensive infrastructure for access roads, parking lots, firebreak etc. Together with the roof surfaces, this constitutes an important rainwater discharge to be managed for which only a diversion canal is available in the direct surrounding area. Furthermore, it has to be considered in this project that the boundary of the water-collection area is cutting the area in half leaving both areas with a different water management. Besides, the area is divided into four groups of buildings and two of them are situated in the water-collection area. The position of the groundwater and the quality of the soil is such that the soil allows the desired water infiltration. However, it is legally prohibited in the water-collection area to implant an infiltration system and consequently a system to buffer the water had to be considered. Aqua-space has been assigned as subcontractor to work out the necessary buffer capacity for this site. First of all, the engineering department made calculations and designed plans to fit into the existing sewerage plans of the separated sewerage systems that have been contracted out. Four basins are planned: one basin for each cluster with a capacity of respectively 175 and 190 m3 for the closed basins within the water-collection area and with a capacity of 170 and 150 m3 for the infiltration basins. The calculation of the buffer capacity is merely based on the hollow spaces (net capacity) between the Leca grains. The pores within the grains have not been considered. The depth of the basins varies between 1 and 1.5 meter. The pipes in and around the basins have been put in such a way that they can be filled backwards. Besides the known advantages of this kind of buffer basins such as durability, environment-friendly, stability and inertia of the Leca grains, the flexible design during the execution of the works is an important advantage. Because this site has a water-bearing underground bearing less load capacity, it was important at the construction of the basins that is was possible to make an appeal to the easy consolidation of the grains without the later function of the basin being disturbed. Rigid systems would suffer from this. Thanks to the small weight of the grains (up to half lighter as the soil being excavated) these basins can function at the same time as compensating foundation. „



Geotehnika referentse Euroopast (ENG)