Assessment Of Impacts Of Ground Movements On Existing Structures Adjacent To Excavations

A cut and cover tunnel is being constructed in soft marine clay as part of the 12 km long Kallang and Paya Lebar Expressway in Singapore. The width of the excavation ranges approximately between 40 m and 60 m and the maximum depth is up to 25 m. Such extensive excavation inevitably causes substantial ground movement in the surrounding areas. The structures identified to be affected by the excavation induced ground movements include the bored piles beneath the base of the excavation, several multi-storey buildings supported on deep foundations and a cluster of warehouses on shallow foundations. This paper presents the methodology and analysis techniques employed for the prediction of ground movements and assessment of impacts on the adjacent structures. The role of monitoring is discussed and selected field data is included.