Abstract:Considering the characteristics of tunnel section of Nanjing metro between Gulou station and Xuanwumen station,the deformation of the tunnel,resulting from the excavation in the soft-flow ground with or without relatively hard crust layer,is simulated by centrifuge model tests. It is found that if the ground surface has hard crust layer,the main deformation of the tunnel is crushed deformation on two sides,otherwise,the main deformation is compressive one in vertical direction. Meanwhile,according to the support system and stress distribution of the tube shed and steel arch,the calculation formulas of the crushed soil deformation are established,and the tiny arch effects between pipes are presented. It is shown that the soil strength and the deformation modulus can be strengthened by grouting method,so that the tiny arch is reinforced and the crushed soil deformation is considerably reduced. Based on the in-situ deformation of the Nanjing metro,the ground deformation resulting from the construction of the tunnel in soft-flow ground is analyzed,and the correspondent construction measures are presented.