One north station excavation in 30m of jurong residual soils in Singapore

Abstract

The One-North MRT station is part of the Circle Line at Buona Vista Road in Singapore. The deep excavation involves a 30m deep cut into 20m of Jurong residual soils and 10m of Jurong sedimentary rocks to form a small stabilizing rock berm on the passive side of the wall, adjacent to the INSEAD building complex. The performance of the wall and excavation system is evaluated against field measurements and FEM analysis. Of significance is that the wall behavior showed that the Jurong residual soils behaved like a drained material despite its low permeability (k) values of less than 10-8 m/s. This project illustrate how allowing for judicious lowering of GWT can lead to a safe and economical design of a very deep excavation in tropical residual soils conditions, with very high GWT. For correct c-phi reduction analysis, allowance must be made for possible wall and anchor failure. © ASCE 2010.