Numerical Simulation of Failure Pattern of Overlying Soil during Vertical Jacking Construction

摘要

In order to clarify the failure characteristics and influencing factors of overlying soil during vertical jacking, using secondary development of discrete element program to simulate the construction process of vertical jacking, which reveals the failure mechanism, scope and development path of the overlying soil in the process of vertical jacking. The simulation results were compared with the test results and the influence of different factors on soil failure were discussed. The results show that the shear breakage of the overlying soil has nonlinear characteristics and the existing works assume that the breakage linearly distributes along a specific dip angle is insufficient. The failure range of the overlying soil is significantly larger than the empirical value, indicating that the failure range of the existing research is inaccurate. In vertical jacking, the overlying soil experiences the process of compressive shear, failure crack, fracture extension, breakage penetration, fracture expansion, formation of overlying soil column, soil redistribution, filling of cracks. The failure range of overlying soil decreases linearly with the increase of jacking speed and has a linear relation with the cohesion force and friction angle.