Reliability Analysis Of Slope System Based On Stochastic Response Surface Method

The stability evaluation of slope engineering is a hot issue in the field of geotechnical engineering.However,there are many factors that affect the stability of slope,and most of them are uncertain.The traditional safety factor method does not consider these uncertain factors when it is used to analyze the stability of slope.Therefore,in this paper,the random response surface method is applied to the reliability analysis of slope to provide a scientific basis for the evaluation of slope stability,The main research contents are as follows:(1)Based on the investigation and design data of the landslide in Meigu River Camp,the geological environment and basic characteristics of the landslide in Meigu River Camp are introduced,and the geological model of the landslide is determined.Through the analysis,the slide zone is divided into two parts: the cutting section(front)and the gentle section.According to the deformation of the east area of Meigu River Camp landslide under the rainstorm condition,the sampling position of the slide zone and the description of the drilling core,the parameters of the smooth section slide zone are calculated.The basic information of the random variables in the east area of Meigu River Camp landslide is determined by the comprehensive test data and relevant literature.(2)The basic principle of common calculation methods of reliability is described.The random response surface method with high fitting accuracy and easy to understand principle is selected as the proxy model to calculate reliability.Through the comparison and analysis of the two methods by the explicit function example,we can get the conclusion that the LHS method is more efficient when there are more input random variables,and the fitting accuracy of the random response surface method can be improved by increasing the order.(3)In the case of homogeneous slope,it is simplified to calculate the reliability on the critical deterministic sliding surface,and the failure probability obtained by constructing the function of homogeneous slope by the random response surface method is close to that obtained by the direct Monte Carlo method.In the case of multilayer slope,four representative slip surfaces of non arc shape are selected by fitting the explicit expression of multi-layer slope based on the random response surface method of finite element.The form method is used to calculate the reliability of slope system,and the accuracy is verified with the Monte Carlo method based on LHS,It is concluded that the combination of the random response surface method and the form method can effectively identify the representative slip surface of any shape and calculate the reliability of the slope system.(4)The reliability analysis method of slope system used in this paper is applied to the example of Meigu River Camp landslide project.Calculate the stability of the east area of Meigu River Camp landslide under the natural and rainstorm conditions,use the random response surface method based on the finite element to fit the explicit expression of the safety factor of the east area of Meigu River Camp landslide under the two conditions,select three representative sliding surfaces,use the form method to calculate the reliability of the landslide system,which is similar to the Monte Carlo method based on LHS,Through the comparative analysis of the failure probability of the representative sliding surface and the landslide system under the two working conditions,it is concluded that only considering a single failure mode will underestimate the reliability of the landslide,and the change of water level will affect the stability and reliability of the east area of the Meigu River Camp landslide.