Numerical simulation of excavation and support in shallow underground subway tunnel

During excavation of shallow tunnels, it is very important to construct primary support and secondary lining structures to guarantee the stability of tunnel surrounding rock and construction safety. Based on a subway tunnel project, in this study, the typical support and lining model is established by using the finite difference program. Stress characteristics and deformation patterns of the primary support and secondary lining structures are analysed and discussed, and the influencing mechanisms of different tunneling modes on the stress characteristics of the support and lining structures are revealed. The numerical results show that the benching excavation and support can effectively relieve the stress concentration in the primary surrounding rock support of typical subway tunnel project. The secondary lining, which is constructed after the deformations of the tunnel surrounding rock and the primary support tend to be stabilized, can strengthen and protect the tunnel surrounding rock and the primary support structure, bear part of the surrounding rock load, and serve as a safe reserve for the safety of subway tunnel projects.