Sensitivity Analysis Of Factors Affecting Slope Stability Under Rainfall And Earthquake

As the second largest group of grottoes in Shanxi Province,the Jindeng Temple has a history of more than 1,500 years,which is a magnificent chapter in Chinese grotto art.Disasters such as rock collapse and landslides on the lower slopes directly threaten the stability of the grottoes,and then the value of cultural relics will be greatly affected.Therefore,this paper analyzes the lower slope stability of the grotto,takes the stability factor of the slope as the evaluation index,and mainly studies the influence of the changes of various influencing factors on slope stability under gravity,rainfall,and earthquake.Sobol index method is used to explore the first-order sensitivity and global sensitivity index of each research parameter,also to analyze the importance of each parameter and the influence of the interaction among the parameters on the slope stability.Furthermore,this method provides theoretical guidance for slope stability analysis and reinforcement treatment.Drainage system,shotcrete and anchoring net and other measures are designed to support the slope to ensure the safety and stability of the grotto.The main results are as follows:(1)Taking the rock slope of the Jindeng Temple in Shanxi as research object,the engineering geological and hydrogeological conditions of the study area are summarized,as well as the main results of on-site investigation.The engineering geological conditions of the study area are generalized,and the physical and mechanical parameters of the rock mass are determined.A stability factor model is established and parameters are provided for the sensitivity analysis.(2)The limit equilibrium method is used to do the force analysis of slope under conditions of gravity,rainfall,and earthquake,respectively.The stability factor calculation model when the slope is damaged in plane and wedge is established as the analytical mathematical model for sensitivity analysis of the slope stability.This model takes the stability factor F for evaluating the slope stability as the objective function,selects the slope geometric parameters and the rock and soil parameters as research parameters,and decomposes the objective function into single parameters and the sub-items of the interaction among different parameters.The importance of each research parameter and the interaction effect among the parameters are investigated.(3)Sobol index method of MATLAB software is used for sensitivity analysis of the influencing factors of the slope stability under the effect of gravity,rainfall and earthquake.The sensitivity of the influencing factors under different working conditions are obtained.Based on Hoek-Brown strength criterion and rock mass GSI system Mohr-Coulomb strength criterion of the conversion between rock mass parameters,the sensitivity of the influencing factors of the slope stability of GSI system are obtained.The sensitivity analysis results put forward effective reference for the slope reinforcement design.The main sensitivity analysis conclusions are as follows: the plane failure model shows that the slope geometric parameters have little influence on the stability,while it is much more sensitive to inclination angle and internal friction angle of the weak interlayer,that is,the property of the structural plane is the major factor affecting the slope stability.Under rainfall condition,the water-filling height,depth and location of tension fracture are highly sensitive,while the sensitivity of hydrodynamic pressure related parameters is low.The parameters related to seismic action are highly sensitive which control the stability of the slope,but the slope will not slide under gravity.While,when the water filling height of tensile fracture is relatively high,a hydraulic driven failure will occur.The analysis results of wedge failure model indicate that unstable failure of slope will happen under gravity without external force factors once a wedge formed by two cut-through structural planes during slope evolution.Further,parameters related to larger-area structural plane are much more sensitive,and the influence on slope stability is greater.There are 135 figures,66 tables and 163 references in this paper.