Multiple-slides back analysis of slope complex failure, case study of Jajarrn Mine

This paper presents a procedure of ill-posed problem back analysis of multiple landslides to determine the reliable shear strength parameters of rock mass. This procedure includes field investigations, determination of instability mechanism, definition of collapse surface on the representative section, limit equilibrium stability analysis for variable shear strength properties, and limiting the range of possible answers. This procedure was applied for two individual complex translational-rotational landslides in Jajram Golbini No.07 mine. The investigations indicate the similarity and spatial correlation between the mechanical (shear strength) attributes of sliding surface of both landslides. This provide an opportunity to establish two equations for determination of shear strength parameters. Then, the cohesion and friction angle of rock mass were determined by solving these system of equations. The results of back analysis provide very useful information about shear strength parameters of rock mass and fault that can be applied for reliable redesign of mine slope.