Statistical Analysis And Grading Evaluation Of Factors Affecting The Stability Of Loess Slopes

In recent years,geological disasters have occurred frequently in my country,among which the instability and damage of loess slopes is one of the more frequent geological disasters.The loess slope disaster has caused huge losses and impacts on our country.According to statistics,the number of loess slope disasters in China is still on the rise.Therefore,it is necessary to systematically and comprehensively analyze the failure mechanism of loess slopes and the factors affecting slope instability based on the geological disaster data information publicly released by the state.This paper establishes a disaster database and performs statistical analysis on more than400 loess slopes collected,using numerical simulation software,limit equilibrium method,grey correlation method and fuzzy comprehensive evaluation and other analytical methods to determine the weight of each influencing factor.The principle of maximum membership is used to evaluate and check the stability of loess slopes,and to evaluate the stability of loess slopes along the Huangyan Expressway.The specific research work is as follows:(1)Collected and sorted out more than 400 examples of loess slope destruction projects in the Loess Plateau,sorted out and analyzed external influence factors such as rainfall,earthquakes,groundwater,river erosion,human activities,and internal influences such as slope height,slope,and soil properties The influence law of factors on the stability of loess slopes,thus establishing a loess slope disaster library based on the main influencing factors.(2)Based on the statistical information of more than 400 loess slope disaster databases,the slope height,slope and soil properties of the loess slope were statistically analyzed,four failure modes of the slope were determined,and each of them was statistically analyzed.The three most important external influencing factors under the damage mode,and then the four damage modes are subdivided into twelve sub-categories,and then semi-quantitative analysis of the main influencing factors of the twelve different damage categories based on the database information,to determine The parameter value range of the influencing factors of loess slope under each category.(3)Determine the value ranges of different types of loess slope influencing factor parameters according to the established loess slope disaster database,use the numerical analysis software Geostudio to establish the slope model,and analyze the main influencing factors through the strength reduction and gray correlation method.Carry out parameter sensitivity analysis to determine the weight value of each influencing factor.On this basis,learn from the existing loess slope stability classification standard,and use fuzzy comprehensive evaluation method to deal with the twelve representative damages in the loess slope disaster library.The classification of slopes is evaluated,combined with the actual disaster characteristics of the slope cases,to verify the accuracy and applicability of the classification evaluation method.(4)Using the empirically calculated slope stability classification evaluation method,the stability evaluation analysis was carried out on five typical slopes along the Huangyan Expressway.The results showed that the selected loess slopes were mainly in a relatively unstable state.The main inducing factors are rainfall,groundwater,artificial excavation disturbance,earthquake and other factors,and the main types of instability failure are shear-slip mode.