Abstract The stability of lining structure of Langyashan restricted cylinder surge chamber in the rock masses with steep obliquity is analysed by using three-dimensional nonlinear FEM. The analytical method of surge chamber’s lining and surrounding rock stressed jointly is presented，and the computing formulae and methods of crack width and reinforcement rate are alse given. By computing for various schemes，the force-bearing state of the lining structure of cylinder surge chamber with bifurcation is illustrated，and a better numerical analysis method for similar cases is presented.
