Study On Stability Of High Cutting Slope Under Rainfall And Earthquake

With the continuous development of road traffic network construction,the number of highways,as the foundation for economic and cultural exchanges between regions,is also increasing.Especially in economically underdeveloped areas,there is an urgent need for more highways to strengthen regional connections.However,during the construction process of highways,deep excavation and high slopes on both sides of the road often need to be treated.The stability of the slope largely determines the safety of the expressway,and the stability of the slope is highly sensitive to the engineering geological environment.Therefore,it is of theoretical value and practical significance to carry out research on the stability of high cutting slopes under adverse conditions.Taking the expressway connecting Kathmandu to Nijgadh in Nepal as the engineering background,this paper selects the high cutting slope of the typical section of Ch26+680 as the research object.Based on the actual situation,a three-dimensional slope model is established by using the finite Metacomputing software Midas GTS NX to study the high slope under different rainfall intensities Stability and structural deformation patterns under different seismic peak accelerations and combined rainfall earthquake effects;A composite support structure consisting of anchor rods,anchor cables,and frame beams was designed for the stability of slopes under the coupling effect of rainfall earthquake and the locations where shear failure is most likely to occur.The stability and deformation characteristics of slopes before and after reinforcement were compared and analyzed.The specific research content and results are as follows:(1)During continuous rainfall,the safety factor of the slope continues to decrease,and the greater the rainfall intensity,the greater the decrease in safety factor.Under rainfall conditions,the negative pore water pressure area on the slope surface first transforms into a positive pore water pressure area.The greater the rainfall intensity,the smaller the range of negative pore water pressure area,and the larger the range of positive pore water pressure area.As the intensity of rainfall increases,the maximum seepage velocity of rainwater inside the slope gradually increases and approaches a limit value.The maximum shear strain of the slope increases with the increase of rainfall intensity.When the rainfall intensity is low,the slope mainly exhibits settlement displacement in the Z direction,with the maximum displacement at the top of the slope.When the rainfall intensity is high,the slope mainly exhibits lateral sliding displacement in the X direction,with the maximum displacement of the soil near the soil rock interface.As the intensity of rainfall increases,the maximum total displacement of the slope and the maximum displacement in each direction increase accordingly.(2)The safety factor of slopes under earthquake action exhibits a fluctuating pattern.The larger the peak acceleration of the earthquake,the greater the amplitude of the safety factor change,and the lower the safety factor at the final moment.The earthquake action causes stress concentration at the position of the soil rock interface.As the seismic peak acceleration increases,the range of stress concentration area increases,the maximum stress value increases,and the maximum shear strain generated by the slope also correspondingly increases.When the earthquake intensity is small,the slope mainly exhibits settlement displacement in the Z direction under earthquake action;When the earthquake intensity is high,the slope mainly exhibits lateral sliding displacement in the X direction.(3)The slope has the lowest safety coefficient and the worst stability under the coupling effect of rainfall and earthquake.The maximum total displacement,maximum displacement in each direction,maximum shear strain,and stress at the soil rock interface all exceed the corresponding calculation results under a single rainfall or earthquake condition.Based on the stability of the slope under coupled working conditions,a combined support scheme of anchor rod,anchor cable,and frame beam was designed.This support scheme effectively improves the stability and integrity of the slope,significantly reducing the total displacement and displacement in each direction,providing a design basis for similar projects.