Strata consolidation subsidence induced by metro tunneling in saturated soft clay strata

Abstract

To choose the optimum construction method of metro tunneling, we conducted research with numerical simulation on strata consolidation subsidence by dewatering, dynamic dewatering, and non-dewatering construction method, taking the integrated effects of fluid-solid coupling and tunneling mechanics into account. We obtained the curved surfaces of ground surface subsidence and strata consolidation subsidence. The results show that the quantity of ground surface subsidence is 31 mm for the non-dewatering method, 39 mm for the dynamic dewatering method, and 105 mm for the dewatering method. Their ratio is 1:1.3:3.4; and the percentages of strata consolidation subsidence to whole ground surface subsidence of each construction method is 27% (no-dewatering), 50% (dynamic dewatering), and 79% (dewatering). It is obvious that the non-dewatering construction method is the most effective method to control the strata consolidation subsidence induced by metro tunneling in saturated soft clay strata, and it has been successfully applied to the construction of the Shenzhen metro line 1.