Load-transfer-associated settlements of a piled building during shield tunnelling in soft ground

Abstract

This study investigates the response of piled buildings to shield tunnelling in soft ground based on both a case history and numerical modelling. The findings indicate that building settlement can be significantly affected by the position of the tunnel relative to the pile foundation. Basically, two different settlement patterns of the pile toe are observed when the tunnel is excavated below and to the side of the pile foundation, implying the presence of different load transfer mechanisms: when the tunnel is excavated on the side of the pile foundation, the loads carried by the raft and pile shaft are transferred to the pile toe. The foundation may settle by compressing the pile-tip soil. In contrast, when the tunnel is excavated below the pile foundation, the loads carried by the pile toe are transferred to the pile shaft and raft. Unloading in the soil above the tunnel crown gives rise to foundation settlement. Notably, the settlement of the foundation in the latter mechanism is shown to be more significant.