Stability Analysis Of Slope Based On Green-Ampt Infiltration Model Under Heavy Rainfall

With the promotion of China's "the Silk Road Economic Belt and the 21st-Century Maritime Silk Road" economic development strategy,the important infrastructures such as transportation and energy in the mountainous areas of the northwest are in full swing,and the construction of urbanization is steadily advancing.The problem of slope engineering involving unsaturated soils is increasing gradually,and the extreme weather events are frequent.The possibility of slope failure induced by rainfall infiltration is increasing.It is one of the most critical issues in the prevention and control of landslides under heavy rainfall conditions that how to make effective forecasting of rainfall-type landslides as much as possible.Although scholars around the world in the heavy rain caused the mechanism of the slope instability and its forecasting research has been fruitful,but existing rainfall landslides warning model more from the experience statistics,physical and numerical simulation.There are few theoretical models that can be directly and effectively applied to slope stability analysis under continuous or intermittent heavy rainfall conditions.Therefore,based on the existing research results,the Green-Ampt infiltration(GA)model is used to explore the process of strong rainfall infiltration of soil slope under different heavy rainfall types,and the stability analysis of slope is carried out by using the limit equilibrium method.What's more,the sensitivity analysis of the infiltration characteristics and stability factors of the slope was carried out by using the improved grey correlation analysis method.The main work and research results are as follows:Firstly,Hydrus-1D software is used to simulate rainfall infiltration process,where the variation law of soil moisture content and wetting front depth under different rainfall intensities is discussed.According to the rainfall duration when the volumetric moisture content of surface soil reaches the saturated state and the depth of wet front at saturation,the heavy rainfall is defined that the ratio of rainfall intensity and saturated moisture content of soil is greater than 10.The stratified hypothesis under the action of heavy rainfall is verified.Applicability,a GA model suitable for this stratified hypothesis is proposed.Secondly,an analysis model of persistent strong rainfall infiltration is established based on GA model,which is suitable for slope and can comprehensively consider the stratified hypothesis and the saturation layer seepage.Combining wetting front and interface in the stability analysis,a calculation model for the stability coefficient of soil slope during the whole rainfall infiltration is proposed.Then,considering the influence of dry-wet cycles on soil permeability and soilwater characteristics of slope,a degenerated GA model suitable for intermittent heavy rainfall is proposed,and considering the deterioration effect of dry-wet cycle on soil strength,the slope stability expression under intermittent heavy rainfall is established.Finally,aiming at the deficiency of the traditional grey relational analysis method,a method of determining the resolution coefficient ? which can take into account the integrity,dynamics and anti-interference at the same time is proposed.The calculation method of the weight and correlation degree of reference data is improved appropriately,and a grey correlation model is established to analyze the sensitivity of rainfall infiltration depth and the influencing factors of slope stability under rainfall.