Stability Analysis Method On Rock Slope Based On Stereographic Projection And Reliability Theory

Aiming at the engineering disaster of rock slope in mountainous area.This paper relies on the national science and technology support plan project “study on diaster process control theory and dynamic control technology of highway subgrade in southwest mountain area”(No.2015BAK09B01).The selection of discontinuity and the analysis of discontinuity parameters of rock slope are carried out by using the principle of stereographic of stereographic.The main work and achievements of the thesis are as follows:(1)A stability analysis method of slope is proposed on the basis of summing up and analyzing the stereographic projection and real proportional projection.Combining the stereographic projection method with the real proportional projection method.The friction circle and friction cone is applied to the stereographic projection.And friction resistance is introduced into it.Stability analysis and safety factor calculation of rock slope are carried out.(2)A probabilistic analysis method of wedge failure is proposed based on stereographic projection for rock slope with multiple and complex discontinuity.The possible sliding zone of wedge could be first determined.The possible sliding intersection lines are selected and the range of calculation is reduced.The intersection lines of discontinuities are simulated by Monte Carlo simulation based on the two-dimensional empirical distribution.The simulation method is proved reasonable by comparing the mean orientation of the sample with the mean orientation of the objective.Joints are categorized into several clusters by using quick clustering analysis.Symmetric axis center of the possible sliding zone is selected as the initial rallying point.The dominant intersection lines of discontinuities of the possible sliding zone are obtained by iterative calculation.(3)In order to solve the uncertainty of shear strength parameter of discontinuity.The double reduction coefficient method and fuzzy set theory method are proposed to analyze the reliability of wedge.The slope of different height is analyzed by double reduction coefficient method based on limit analysis method of wedge by Hoek.Amplification ratio of reduction coefficient is proposed,and the accuracy of the amplification ratio is verified by the reliability theory.The results show that as thewedge height and the unit weight of rock increase,the stability of slope gradually reduces.During the analysis of double reduction coefficient,the variation amplitude of cohesion is relatively small while the variation amplitude of internal friction angle is large.The stability of slope is dominated by the internal friction angle,so the reduction value of internal friction angle in double reduction coefficient analysis can be regarded as the safety factor of wedge.Because of the uncertainty of discontinuity shear strength parameters.In this study,the uncertain parameters are expressed as fuzzy numbers and fuzzy set theory is employed.The Monte Carlo simulation technique and reliability index approach are implemented with fuzzy set theory in the evaluation of the probability of failure.(4)In order to find out the stable state of wedge from its deformation.A new method of wedge displacement analysis is proposed based on the stereographic projection.The force of wedge is analyzed by the stereographic projection.Due to the different influence degree of the wedge discontinuity shear strength on the wedge stability.The weight parameters of the wedge discontinuity are derived on the basis of its stress characteristics.The weight parameters are listed separately.Only considering the internal friction angle.Considering the internal friction angle and cohesive force.The internal friction angle,cohesive force and head pressure are taken into consideration.The test data and related specifications are referenced.The maximum shear displacement of a single discontinuity is quoted.The maximum shear displacement of wedge is calculated by using the obtained weight parameters.The safety factor of wedge is setted to deduce the critical displacement value.The relationship between the displacement of the monitoring point and the maximum shear displacement is determined according to the relationship between the location of the monitoring points and the intersection lines of discontinuity.