Based on the initial stress method for elastoplastic finite element

analysis an iteration procedure for elastoplastic stochastic finite element analysis is proposed

and a method of reliability assessment for stability of surrounding rock is suggested based on the theory of structural reliability. The mean value and standard deviation of shotcrete’s stresses can be obtained. Corresponding computer program for elastoplastic stochastic finite element analysis and for reliability calculation of the safety of tunnel is developed .Two illustrative examples are presented; the first numerical example is examined to show that the proposed method yields accurate results compared with the direct difference results; the second example is for the stability analysis of tunnel; some useful conclusions are also obtained.