Model Test Study On Slope Instability Induced By Rainfall

Accumulation slopes are widely found in mountainous residential areas,on both sides of roads and rivers in our country.Due to its complex composition,discontinuity and inhomogeneity in structure,accumulations have brought great difficulties to the research.The current research on accumulations still has certain limitations.Accumulation landslides are a common geological hazard,which is easy to slide during summer and other periods of abundant rainfall,posing a serious threat to local residents and road traffic.Therefore,it is of great significance to study the slope of accumulation body in depth.Based on previous studies,this paper generalizes the geological model of the accumulation body slope.Using the soil in the Huaipa landslide in Mianchi County,Sanmenxia as the research material,based on the outdoor rainfall-type landslide model test,the landslide model has an in-depth study on the rainfall intensity of the landslide model.The evolution process under the condition of 30mm/h continuous rainfall for 3h(the rainfall when the local red warning is issued),and the response law of pore water pressure,earth pressure,settlement and horizontal displacement is obtained,and the influence of bedrock surface inclination angle on accumulation landslide is discussed.The development and development and the influence law of deformation and failure.The main research results are as follows:(1)According to the generalized model of the dual structure accumulation body slope,the impermeable bedrock surface is established in the model box,and with the help of the model test system,three sets of slope angles of 20°,30°,and 40° are carried out.Model test of layered slope.(2)According to the model test results,the deformation and failure modes of bedding slopes with different bedrock inclination angles are proposed: when the bedrock inclination angle is 40°,the failure mode is a sliding landslide,and the failure process is:rainwater infiltration-trailing edge pull cracks-rainwater Drive the fine particles to move down the slope direction-pull cracks to accelerate expansion-the base cover interface forms a water retention layer-the overall destruction.When the bedrock inclination is 30°,the failure mode is a traction landslide,and the deformation failure mode is: rainwater infiltration-gully at the toe of the slope-sliding at the toe of the slope-tensile cracks in the middle part-creeping down the slope in the middle part--Pull cracks in the rear edge-sliding in the middle-sliding in the whole.When the bedrock dip is 20°,it remains stable under the conditions of high rainfall intensity and long rainfall time,and it is considered to be a stable slope.(3)Under the condition of heavy rainfall,settlement cracks are generated at the rear edge of the slope with an inclination of 40°,which accelerates the infiltration of rainwater,and the soil slowly creeps downward under the action of rainwater flow,causing the cracks on the rear edge to expand.As the rainfall progresses,the movement of fine particles causes the front edge pores to be blocked,forming a stagnant layer inside the slope,and the effective stress is reduced,resulting in the overall instability of the slope.The soil at the front edge of the slope with an inclination of 30° produces a gully under the action of rainwater,and the rainwater enters the interior of the slope,causing the slope toe to soften and slide first.After losing support,the soil in the middle and the top part of the soil was pulled and cracked one after another,and the soil moved to the toe of the slope with the flow of rainwater,which eventually caused overall instability.(4)Using the FLAC3 D numerical simulation method,the numerical calculation model of bedding slopes with different inclination angles of 20°,30°,40° was constructed,and the results of the model test were compared and analyzed in terms of horizontal displacement,maximum principal stress,and plastic zone distribution.