Parameter optimization of corrugated steel initial support structure of mountain tunnel based on sensitivity analysis

New corrugated steel initial support in mountain tunnels, as a kind of assembly structure, can achieve purposes of rapid construction, green environmental protection. However, optimization design of corrugated steel initial support in mountain tunnels is seldom researched. In this paper, Qipanshan Tunnel in Yunnan Province is taken as engineering background. Numerical simulation calculation is carried out by ABAQUS. Combined with sensitivity analysis of tunnel convergence, internal force of corrugated steel and second liner, the design parameters of wave thickness, wave height and wave pitch of initial support of corrugated steel are optimized. Research shows that sensitivity analysis method can be applied well in the optimization of tunnel innitial support parameters. Effectively improving internal force of corrugated steel and secondary lining can be achieved by adjusting thickness of corrugated steel. Optimization effect of parameters of corrugated steel is more obvious in the RDP range of 0.333 ∼ 0.375.