Prediction of behaviour of a deep excavation in soft soil: a case study

Abstract

In this paper, the nature of wall deformation and surface settlement for deep excavation in soft soil was studied. Excavation was carried out in eastern metro city of India in the bank of Hooghly River. This excavation was the part of underground metro station construction. Numerical analysis was performed to predict the soil behaviour during excavation. Accordingly, the most suitable excavation method was finalised. Vertical and horizontal deformations were measured during construction on adjacent area to ensure the safety of nearby existing structures. Predicted deformation was relatively high when compared with measured one. Back calculation from measured deformation shows the conservative estimation of stiffness during investigation and anisotropic soil behaviour. This study indicates that the numerical analyses can be very effective tools to predict the behaviour of soil during excavation with installation of support systems. Thus, it helps for necessary planning to ensure the safety of nearby structures. However, accuracy of such analysis depends on the judicial estimation of soil parameters.