Abstract: 3D numerical simulation analysis by means of finite element and fluidsolid coupling methods is made for the dewatering and excavation of a vertical shaft of a running tunnel of Shenzhen Metro Line 5 constructed by mining method, so as to assess the ground surface settlement induced by the sinking of the vertical shaft. The variations and distributions of ground surface settlement induced by dewatering and excavation of the vertical shaft are obtained. Conclusions drawn are as follows: 1) The ground surface settlement induced by the excavation of the vertical shaft without dewatering is far smaller than that induced by the coupling effect of dewatering and excavation of the vertical shaft; 2) The closer the measurement points to the vertical shaft, the larger the ratio of the ground surface settlement induced by excavation in the total value; the farther the measurement points to the vertical shaft, the larger the ratio of the ground surface settlement induced by dewatering in the total; 3) At the position with the larest ground surface settlement, the settlement induced by dewatering occupies 65% of the total.

Key words: Metro tunnel, shaft sinking, dewatering, settlement, numerical simulation