Probability Analysis Of Reservoir Bank Slope Under The Condition Of Rainfall And Water Level Fluctuation

Reservoir landslide is one of the common geological disasters,the effects of rainfall and reservoir water level are the main cause of the displacement and instability.How to reduce the occurrence of landslides has become the focus of attention,and limit equilibrium method(LEM)is a common method that is used to evaluate landslide stability,which is based on geological survey,buildinng relevant geological model that can lead to the slope meet the equilibrium of force or torque and calculate stability coefficient.Whether the stability coefficient is more than one determined the slop stability.But the defect is not taking into account the effect of uncertainty factors of landslide and the randomness of soil shear strength parameters changes(such as c,?),such as the randomness ofrainfall intensity,water level rising and falling height and rate of changein the external environment,which arereasons why according to the fixed value stability coefficient calculation analysis method is more than one but the slope damaged.The method of failure probability takes the boundary condition and the uncertainty of the calculation parameters into consideration,it regards the stability factor as a random variable under the influence of various factors,Based on the failure probability analysis of landslide,the stability of the landslide is obtained.Therefore,the probability method is more consistent with the analysis and evaluation of the stability of landslide.This paper based on the study of the accumulation landslide located in the Three Gorges Reservoir Area,China.Firstly,obtaining the relationship between the stability of landslide and rainfall and the drop of reservoir water level through the analyzing engineering case;Secondly,the building of standard slope model,and the applying of unsaturated soil mechanical theory,can simulate the changing range of water content at a point under the condition of rainfall and reservoir water level drop,The different water content on shear strength of sliding soil through three axle shear experiments,and using the K-S test method of shear strength parameters of slip soil types of probability distribution.Finally,taking the Ercengyan landslide located in Wanzhou District of the Three Gorges Reservoir Area for example,combined with experimental data and numerical simulation technology and analyzedthe failure probability and stability of the slope under rainfall and reservoir water level drop,the main study is shown in the following aspects:(1)To investigaterainfall and the drop of reservoir water level drop on the water content of the landslide.analysis method of slope stability under the condition of rainfall infiltration.Strength Theory of Unsaturated Soil is discussed,which includes stress state variables of unsaturated soil and Fredlund shear strength theory of unsaturated soil,the influence of rainfall process on the stability of landslide is analyzed by the method of finite element strength reduction and through discussing matric suctionsaturation and water content at a point of slope,the effect of water level drop height on soil water content was studied.The variation range of water content is calculated according to the law of saturation.(2)Analysis of the strength parameters of slip soil test results and its probability distributionof different schemes The variation of shear strength parameters and the distribution types of soil under different water content are simulated by three axis compression experiment.nd using the K-S test method of shear strength parameters of slip soil types of probability distribution(3)Study on the variation law of landslide failure probability Taking the Ercengyan landslide in Wanzhou District of the Three Gorges Reservoir Area for examplebuilds geological model of the Ercengyan landslide and analysis of landslide stability calculation condition and combines numerical simulation to analyzethe variation disciplinarian of the failure probability under the condition of rainfall and reservoir water level drop.