Monitoring and analysis of results for two strutted deep excavations usingvibrating wire strain gauges

As part of the North East Line Mass Rapid Transit Project in Singapore, Con tract 704 included the construction of two underground station structures. The excavation for Serangoon Station was in the residual Bukit Timah granit e and the excavation for Woodleigh Station was in the residual Old Alluvium material. The temporary retaining structures for both excavations consiste d of driven soldier piles and timber lagging supported by steel struts. The excavation for the construction of both stations was monitored in part usi ng vibrating wire strain gauges on the struts. This paper presents the stru t monitoring results. A comparison is made with the apparent earth pressure envelopes recommended by Peck. The need to balance continued development w ith the land constraints in Singapore means that underground structures wil l continue to be used. The results presented in this paper are relevant in determining the geotechnical parameters for deep excavation retaining walls constructed in these types of materials. It is concluded that the measured earth pressures relate reasonably well to the apparent earth pressure enve lopes recommended by Peck. (C) 2001 Elsevier Science Ltd. All rights reserv ed.