Improvement of the Strength Reduction Method on the Basis of FLAC3D in Slope Stability

Traditional strength reduction methods employ same reduction factor to get safety factors of frictional angle φ and cohesion c of slide slopes. In the actual slope destruction, however, different shear strength parameters have different action effects. For this reason and considering that sliding resistance effect of sliding mass is much bigger than the difference of shear resisting factor φ and c. Taking a side slope for example, the finite difference software FLAC3D is used to search the cut-through area of shear strain increment under limiting condition to find potential slip surface. Then the shear resisting factor φ and c of sliding mass are reduced. Each reduction method has different safety factors and slip surface, and several slip surface form a potential gliding area. Results indicate that the traditional single safety factor method is a special case of two safety factors method. With increasing strength reduction factors of frictional angle and cohesive force, gliding surface gradually moves from deep layers to superficial layers. Slip surfaces found by different strength reduction methods form a certain gliding area with the sole reduction of shear resisting factor φ and c as its upper and bottom boundary. Stability analysis by two safety factors is more accurate than that by traditional strength reduction method and provides reliable technical support for study of side slope stability and its reinforcement.