Effects of Soil-Structure Interaction on Wall Deflections and Surface Settlements During Deep Excavations

Abstract

Ground movements due to excavations may cause damages to structures. While wall deflections could be adequately predicted, accurate estimations of ground movements are usually far from field observations. It has been identified that the behaviour of soil at small strain plays a key role in predicting the surface settlements. Presented herein is a study on a well-documented excavation case history in soft ground located in Taipei Basin. Two-dimensional finite element analyses adopting the hardening soil with small-strain stiffness to simulate the nonlinear stress-strain relationship of soils have been conducted. Various interface reduction factors have been adopted to simulate the soil-structure interaction. The effect of water pressures on the performance of excavations was studied. The analyzed results show that the hardening soil with small-strain stiffness model could reliably predict the wall deflections and the surface settlements simultaneously. The interface reduction factor would be the key parameter for exploring the ground movements due to deep excavations.