3D Elasto-plastic Numerical Simulation of Entire Construction Process for H ighway Tunnel

In order to obtain the regularities of stress, strain and displacement of tunnel structures during excavation, the northern end ofBijiashan tunnel in the 2nd stageYu-Qian projectwasmodeled and its construction process was numerically simulated with 3D elasto-plastic finite elementmethod (FEM). Comparison between simulated and in-situ tested results shows that the range with a great influence of tunnel excavating on surrounding rock is5m around an excavation face, excavation of the upperbench has a greater effect than that of the lower bench, and one-third of total settlement and horizontal displacement of surrounding rock has generated before excavating. In addition, the plastic zone in surrounding rock ranges 1. 5 m in the front of an excavating face, and rock bolts are mainly influenced by the excavation of the upperbench in the current construction step.