3-D finite element analysis of ground settlement caused by shield construction of metro tunnels in soft soils

The s hield tunneling method is a common construction one for underground tunnel s widely used in soft soils . B ut people still lack adequate knowledge and engineering experience on the reasons and mechanism of soft soil movement and ground settlement caused by the excavation of shield tunneling, which needs further investigation. Hence, take n the excavation of the subway internal tunnel of Hangzhou Metro Line No. 1 for an example, three-dimensional nonlinear finite element simulation and analysis are made on the excavation process of metro tunnel shield by using numerical methods. The curves of ground movement and settlement of soils around the tunnel caused by shield construction are acquired. The variation rules of transverse and longitudinal ground settlements caused by shield construction as well as the trend and distribution of the settlement s at different depths are obtained and analyzed. Some useful conclusions are drawn for the design and construction of metro tunnel s in soft soil area.