Abstract: The Wujiang landslide at right bank of Wujiang Canyon is located at the entrance region extension project of Centian river reservoir., The distance from the downstream slope to dam is only 300 meters, which is a typical ancient landslide with a total volume of 1 327×104 cubic meters. The stability of Wujiang landslide significantly affects the operation and safety of the dam and discharge structure. The observed displacement of landslide is analyzed in this paper. The strength parameter of landslide is determined by limit analysis method with an assumption of safety factor of 1.0 during slow creep. The internal displacement of landslide is observed creep annually in the borehole observation. Assuming that the landslide satisfied Mohr-Coulomb yield criterion, viscoplastic strain rate is calculated using based on the assumption of Perzyna, the finite element calculation program of elasto-viscoplastic is adopted to analysis the landslide combined with the finite element model of typical profile of landslide, thus the elastic modulus and viscosity coefficient of landslide and sliding zone are obtained with inversion by the combination of orthogonal design and optimization algorithm, the results can provide the basis for stable deformation analysis and monitoring of the landslide and offer reference for similar projects.

Key words: landslide, sliding zone, measured deformation, elasto-viscoplastic parameters, feedback