Accumulated deformation characteristics of silty soil under the subway loading in Shanghai

The deformation of silty soil under the subway loading was explored and analyzed by the dynamic triaxial tests for the undisturbed soil around the tunnel of the Guoquan station of Line No. 10 subway in Shanghai. The results show that accumulated deformation of soil can be divided into three stages: the sharply increasing stage, the gradual stability stage, and the smooth stage. In this paper, uniform design was used to arrange the experiment by fully considering the factors of affecting accumulated deformation, such as the frequency ratio, the cyclic stress ratio, the consolidation ratio, the overconsolidation ratio, the vibration times ratio as well as their interactions. The regression equation and evaluation model of soil deformation were established by mathematical statistics approach. It also shows that the main factor of subway tunnel is the cyclic stress ratio; however, the interaction between the frequency ratio and the consolidation ratio has the least effect compared with other factors. These studies provide some valuable references to the design of the subway tunnel. Copyright Springer Science+Business Media B.V. 2012