Deformation model and stability probability analysis for deep-thick accumulation body slope in lenggu hydropower station

It is an important engineering problem to evaluate the stability of deep-thick accumulation body in many hydropower stations in the west China. The deformation mode and production mechanism affects directly its stability. Take Mahe accumulation body in Lenggu hydropower station as example, the boundary conditions and deformation failure mode are analyzed in this paper. The mechanical strengthen parameters of the accumulation body are determined by use of field investigation, indoor test and back analysis. The gained parameters are processed by probability method. Two methods for deterministic slip surface and nondeterministic slip surface are used to calculate the safety coefficient by probability method. The results shows that: the stability of the accumulation body in the condition of two dimension is poor, and the failure probability is small in three dimension.