Tunnel Reliability Analysis Based on the Combination of Modified FOSM and Numerical Calculation Program

Evaluate the reliability for the deformation of structure is a hard work. Usually stochastic finite element method or response surface method was adopted. In this paper, a new way by combining of numerical method and modified reliability analysis method is proposed. The modified first order second moment method (FOSM) was introduced and three examples are employed to verify the feasibility and the effectiveness of this method. The examples showed the modified FOSM had the advantage of faster convergence rate, higher calculation accuracy in comparison with FOSM, response surface method and optimization algorithm method. Combining finite element method program with modified FOSM method is applied to analyze the reliability index of deformation of a tunnel. The results showed this approach was a successful method to analyze the reliability of complex structure.