The Failure Mechanism And Stability Analysis Of Earth-rock Mixed High Slope In En-Lai And En-Qian Expressway

En-Lai En-Qian highway is an important channel in southwest Hubei province into Hunan and Guizhou.It is an important infrastructure to improve the transportation conditions and promote regional development.According to the route planning and design,some of the mountains will be excavated and filled.Part of the construction plan will change the geological and environmental conditions along the route.During the construction of the whole highway project,there are numerous disasters and prominent disasters.The problems of slope disasters often lead to more than expected construction cost and construction period.If the problems of slope disasters are not properly handled,it would also be devastating for the lives of people in disaster areas and for the lives of construction workers.Irreparable damage was caused to the construction of the project,and it would also cause irreparable damage to the construction.Therefore,it is necessary to study the mechanism and stability of the slope failure.The research results have important reference value for the stability analysis,regulation engineering and monitoring of the landslide and cutting slope in the mountainous area of the region in the future.The typical earth-rock mixed slope is selected as the research object.Use FLAC3 D numerical calculation software as the computing platform,according to the platform open source features,based on the strength reduction method,Study on the failure mechanism and stability of earth-rock mixed high slope by the calculation program in fish language,The main tasks completed are as follows:(1)Study on the calculation method of the stability of earth-rock mixed slope.Using the FLAC3 D Extrusion function reference to slope engineering geological profile modeling,according to the traditional strength reduction method,fish statement is used to adjust the calculation process,the regional reduction of the strength of rock soil in the slope is realized.The real-time record is realized for each state of the strength reduction process.The accuracy of strength reduction and calculation are adjusted according to the calculation.(2)The sensitivity analysis of the stability calculation parameters of the typical earth-rock mixed high slope is calculated.The results show that the change of soil shear angle has less influence on the slope safety coefficient.Soil cohesion and internal friction angle have great influence on the calculation results of safety coefficient.The sensitivity of internal friction angle is stronger than that of cohesion.The elastic modulus and poisson ratio are not sensitive to the calculation results of slope safety factor but are sensitive to the slope displacement calculation results.(3)Through monitoring data and numerical simulation results of the specific engineering examples,using the method of displacement reverse analysis,a set of calculation parameters for the stability of earth-rock mixed slope in the study area is obtained: The elastic modulus and poisson ratio of gravel soil are 60 MPa and 0.35;The elastic modulus and poisson ratio of severe weathering shale are 150MPa?0.3;The elastic modulus and poisson ratio of moderately weathered shale are 300MPa?0.25.(4)The deformation process and failure mode of the mixed slope are analyzed by numerical simulation.According to the comparison between the numerical results and the actual working conditions,on the one hand,it verifies the rationality of the calculation method and calculation parameters of the mixed slope stability.On the other hand,based on the actual working conditions of Wangcheng slope,the deformation development trend and failure mechanism of earth-rock mixed slope in the study area are obtained: Under the action of gravity,due to the artificial excavation has changed the natural state of the slope,the creep of the earth and rock mixture is gradually sliding.At the foot of the slope,the rock mass is extruded.There is a tension crack in the upper edge platform after the slope.And because of the effects of rain,the strength of the rock and soil in the slope decreases gradually,when it's not enough to resist the slide,the creep increases,the potential sliding surface is formed in the slope,and it extends from the slope to the top of the slope,finally,the composition runs through the sliding surface of the whole slope.If appropriate protective measures are not taken,the slope will be destabilized by the failure mode of circular arc sliding along the resulting sliding surfaces.