VALIDATION FOR ROCK BLOCK STABILITY AND ITS APPLICATION TO ROCK SLOPE STABILITY EVALUATION USING DDA METHOD

The process in calculation of the contact forces between blocks is firstly introduces,and a method about the factor of safety calculation in discontinuous deformation analysis(DDA) is then presented. The stability validation with a rock block sliding along a incline has been carried out. Two cases,one with the friction angle ?, and the other with the friction angle ? and cohesion c together,are considered. At last,according to the stability and reinforcement issues of a weak fault controlled rock slope,which is formed by right dam abutment excavation of a hydro-project,DDA method has been used to analyze the stability of the fault controlled rocky slope with the slices used in limit equilibrium methods;and its actual stability states,separately with/without the utilization of rock bolt reinforcement,have been evaluated. It is shown that,for the calculation of the factor of safety along a given sliding surface with DDA method,as the contact forces are based on the rigorous equilibrium equations, where the discontinuous deformation of block system is allowed,the improper assumption for the utilization of shear strength between the sliding slices with a constant ratio is not necessary;and the stability calculation results by DDA method may reflect a more reasonable stability situation of an actual rock slope. In addition,thenumerical simulation of rock bolts to the reinforcement of rock slope in DDA shows an effective role in promoting the stability of rock slope.