Underground Singapore 2011 panels and bored piles were found to accurately correspond with the expectations established in preconstruction studies. Figure 10 present a few selected photos of the excavation face with exposed D-wall panels and bored piles. Construction of the upper tunnel was successfully completed in early September 2010.
D Wall D Wall Panel
Panel
Y39
Y40
Round 6 Top Heading
Round 8 Top Heading Existing Bored Pile PI-9
D Wall
D Wall Panel Y40
Panel Y41
Round 9 Top Heading
Round 21 Top Heading
Figure 10–Photos of Excavated Face at Various Stages
6.
INSTRUMENTATION AND MONITORING
In order to verify the validity of design assumptions, a comprehensive instrumentation and monitoring system was implemented. In addition to ground surface monitoring arrays, optical 3D prisms were installed within the cut & cover structure to monitor the performance of the life running track bed. Monitoring data was accessible online through a dedicated web site. If a particular reading exceeded the alert level during excavation, the system automatically sent out an SMS to the key persons of the project team identifying the instrument location, the alert level and actual current reading value.
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