3D fluid-solid full coupling numerical simulation of soil deformation induced by shield tunnelling

Abstract

For twin tunnels, succeeding tunnelling may cause damage to preceding tunnel in close proximity during excavation. Therefore it is important to predict the soil deformation around the tunnels to ensure safety during shield construction. However, the effect of groundwater is usually ignored and soil parameters are considered constant in previous study. This study has been undertaken using the Biot’s theory and rheological theory. And the parameters of soil are considered to be variable. On that basis, a 3D fluid-solid full coupling mathematical model of soil deformation induced by shield tunnelling is established. Furthermore, the equations are discretized by the Galerkin Weighted Residual Method (GWRM). The analysis of finite mathematical model is developed by FORTRAN95. The mathematical model was proved by comparing the calculated and measured settlement from Chengdu Metro Line 4. And then the soil deformation and the pore water pressure around the tunnels were predicted. The results show that the error between measured values and calculated values of soil deformation is relatively small.