Abstract:Usually it is very difficult to get an analytical equation of limit state for reliability analysis of the stability of tunnel. So,based on numerical simulation,BP network and optimal technique,a reliability analysis method is put forward to calculate the reliability index and test point. This method can simulate the reliability problems with implicit performance functions in actual engineering. On calculation reliability,the deterministic FEM programs can be used directly. Two illustrative examples are presented in this paper. The first example deals with reliability of a frame structure,and the second one studies the stability of a tunnel under the initial stress effect. In the calculation,the Young’s modulus,friction angle and cohesion are treated as random variables and different probability distributions with these random variables and the correlation among them are considered. Comparisons with other methods show that the proposed method is very efficient and reasonably accurate.