Abstract:

The disturbance to soft ground caused by large diameter slurry shield boring is studied, with Chengjiang West Road rivercrossing tunnel in Jiangyi city, Jiangsu province as an example. The main contents and conclusions of the study are as follows: 1) The rules of the longitudinal ground surface settlement caused by shield tunneling are studied, the four stages of the ground disturbance caused by shield tunnel are verified on basis of previous study results, and the percentages of the ground disturbance caused by shield tunneling in different stages are obtained. 2) 3D finite element model is established by means of ABAQUS finite element software and the nonlinear deformation of the ground is considered in the numerical calculation. The numerical simulation shows that the trends of the transverse, longitudinal and vertical displacement coincides with the actual conditions of the works, and the maximum settlement value is close to the measured data; the settlement of the soft ground can be effectively reduced by increasing the values of E, c and φ of upper soil layers, and in turn the disturbance to the ground caused by shield tunneling can be reduced. It is concluded that the settlement and disturbance of the ground can be reduced by means of grouting reinforcement of the surface layers of the ground. 

Key words: large diameter slurry shield, ground settlement, soft ground, grouting reinforcement, numerical simulation