Three-dimensional fluid–soil full coupling numerical simulation of ground settlement caused by shield tunnelling

Abstract

For shield-driven tunnels, the strength characteristics and the over consolidation ratio of the soil are major factors influencing ground settlement caused by shield tunnelling. However, the influence of groundwater was usually neglected. In order to predict the ground settlement caused by shield tunnelling under the influence of groundwater, a three-dimensional fluid–soil full coupling mathematical model was established. This work was based on the Biot’s consolidation theory. And the soil constitutive relation had extended to visco-elastic-plasticity. Besides, the dynamic relationship between soil parameters and effective stress were taken into account. The finite element discretisation equations were obtained by the Galerkin weighted residual method. The finite element method (FEM) program of three-dimensional fluid–soil full coupling model of ground settlement caused by shield tunnelling was developed by FORTRAN. The shield-driven tunnels from Yushuang Road Station to Shuanglin Road Station in Chengdu Metro Line 4 were taken as an example. The FEM program was used to predict ground settlement and pore water pressure variation caused by shield tunnelling. The results showed that the variation tendency of pore water pressure was similar to that of ground settlement.