Coupled numerical analysis of tunnel excavation in saturated soft clay under high groundwater

A coupled numerical simulation of a river-crossing shield tunnel excavation in saturated soft clay with high groundwater has been performed using a three-dimensional finite difference model, which takes into account variation of soil permeability with stress, anisotropy of permeability, reduction effect of joints on segment bending stiffness and the hardening process of synchronized grouting material. Groundwater seepage conditions around the tunnel, bending moment, axial forces and strength safety factor of tunnel segment as well as deep soil displacement during tunnel diving are investigated numerically. The analyses provide valuable information concerning the mechanical behavior of tunnel segment and hydrological field in soil around tunnel during advancing. The result also is benefited to control groundwater for river-crossing tunnel in soft clay under high water table.