Abstract: On the basis of preliminary judging the steady state of dump slope，a safety factor is set，the shear strengths of waste dump bulk materials are inversed with the safety factor.With the use of the common Bishop method and Residual thrust method，the nonlinear equation group is built to make the iterative solution.Meanwhile，the shear strengths of waste dump bulk materials are calculated out.Aiming at the actual inversion analysis on dump slope of a large open pit mine in southwest China，it is concluded that:for fine-grained granular rock with more quaternary topsoil，its cohesion c by inversion analysis is smaller than triaxial test by 0.026 MPa，but friction angle φ is bigger by 3.94°；For hard gabbro with coarse grained soil as the main，its cohesion c by inversion analysis is bigger than that at triaxial test by 0.021 MPa，but its friction angle φ is smaller by 4.06°.Although the two kinds of bulk materials have different inversion analysis and experiment results，the inversion analysis results based on the safety factor can better grasp the shear strength parameters of waste dump bulk materials as a whole.This method is superior to the indoor test and field test which are affected by the unevenness and discreteness of bulk materials.At the same time，the shear strength parameters obtained can be used as the basis of dynamic stability analysis in the late dump planning.

Key words: Waste dump, Safety factor, Inversion analysis, Shear strength, Dump plan