Difficulties in the Construction of Subway Tunnel Underpass Project and Research on Ecological Restoration Technology

Subway construction is a high-risk construction project, because there are many uncertain factors such as Undercrossing urban hinterland and geological conditions, which lead to the difficulty of organization and management and frequent safety accidents. Therefore, there is an urgent need for effective safety risk analysis model and risk management means to prevent accidents. Aiming at the mechanical problems of surrounding rock and supporting structure of subway tunnel under different construction methods, the dynamic numerical simulation of three pilot tunnel method and upper and lower step method is carried out by using finite element method. The transformation relationship between stress field and displacement field of subway tunnel under different construction procedures is established, and the two construction methods are compared. The test results show that the internal force, axial force and bending moment model of the subway tunnel support structure system established in this paper has a certain guiding significance for the design and safe construction of the subway tunnel.