Rock Slope Of Shear Strength Parameter Back Analysis And Engineering Application

In open-pit mine rock slopes engineering, geological hazard including wedge failure and circular failure slip are occurred frequently, which brings immense economic losses and casualties. It’s an effective measure to reduce or avoid geological hazard occurrence by analyzing the slopes’stability and controlling rock slopes reasonably based on the shear strength parameters of rock discontinuity and that of rock mass. The traditional method of obtaining these shear strength parameters has some shortcomings:the in-situ direct shear test needs a long period and high cost, and it is difficult to bring into practice;it’s also hard for laboratory shear test to maintain the discontinuity in its original state as well as ensure the representative of the rock. So it is significant to study on the shear strength parameters of rock discontinuity and the shear strength parameters of rock mass.This paper does research on the shear strength parameters of the discontinuity and that of the rock mass by taking the eastern Phyllite rock slope of Jiu Qu open-pit mine in Yinshan as the research object:(1) The study on the shear strength parameters of rock discontinuity for rock slope. Ascertaining the landside model of slope by field investigation, measuring the relational data of landside by apparatuses such as total station. Then doing graphic analysis on the landside by coordinate projection method, combining it with the lab experiment result, using limit equilibrium method to figure out the shear strength parameters of rock discontinuity through back-analysis.(2) The study on the shear strength parameters of rock mass. Through field geotechnical investigation and the lab experiment to identify the quality of the rock slope and the RMR, preliminarily calculating the shear strength parameters of the discontinuity by the estimation method of Hoek-Brown. Then obtain the data of displacement variation according monitor the deformation of slopes, using the back-analysis of displacement to obtain the shear strength parameters of rock mass.Through the research of this paper, some conclusions are drawn as following:(1) Due to the small scale landside happen occasionally in open-pit mine, we brings a novel method of limit equilibrium and coordinate projection method to obtain the shear strength parameters of rock discontinuity. This method can compensate the shortcomings of the in-situ direct test and other estimation methods, since the engineering applications showed that the proposed method is feasible.(2) According to the results of displacement monitoring and Hoke-Brown criterion shear strength parameters of rock mass are determined by using back-analysis of displacement The cohesive force is0.226MPa, the internal friction angle is12.041°...