Back Analysis about Shear Strength and Deformation Parameters of High Excavated Accumulation Slope in Xiaowan Hydropower Station

Abstract

Proper mechanical parameters of slope rock mass are the premise which ensures the smooth progress of slope stability calculation. By analyzing the geological information of the yinshuigou accumulation slope on ridge 2 in Xiaowan hydropower station, and according to the deformation and damage in the excavation of the accumulation slope, this paper inverts the shear strength parameters of the accumulation slope by using 2D rigid limit equilibrium method. On base of unloading rock mass mechanics methods, the stress and strain analysis to the accumulation slope is studied by using 3D finite difference method, and by contrast of the monitoring displacement and calculated displacement in slope-direction about the key point of the accumulation slope , the article inverts the deformation parameters of the accumulation slope. Finally, the shear strength parameters in the contact zone are ascertained as: C=0.04MPa, Φ=30°, and the deformation parameter of the accumulation slope is changed from the initial 1.5MPa to 0.95MPa by the damage unloading.