Analysis of dam slope stability by double safety factors and dynamic local strength reduction method

Strength reduction method has been widely used in dam slope stability analysis. However the traditional strength reduction method does not take into account the difference of decay rate of cohesion and internal friction angle in the dam slope failure process. Besides, this method discounts the strength parameters of all elements. This paper adopts different reduction factors for material strength parameters, such as slope cohesion and internal friction angle. Based on the yield approach index (YAI) criterion, this paper adjusts the reduction region gradually and puts forward the double safety factor and the dynamic local strength reduction method for the dam slope stability analysis. A case study with a typical example shows that this method can better reflect the decay rate difference of cohesion and internal friction angle in the dam slope failure, further it can provide better simulation for the slope failure processes. The safety factor of this method is generally less than that of traditional strength reduction and dynamic local strength reduction method. This new method can better overcome the two defects encountered in the traditional strength reduction methods.