Landslide Mechanism And Treatment Technology Of Accumulation Slope In Mountainous Area Based On Engineering Stacking Effect

With the steady progress of the ’ Belt and Road ’ and ’ transportation power ’strategy,the construction of transportation infrastructure in the southwest mountainous area is advancing by leaps and bounds.Affected by the topographic and geomorphic conditions of mountainous areas,highway construction often spreads along the middle and lower parts of the mountain,and engineering activities such as manual excavation and filling are inevitable.Engineering loading such as subgrade filling has become the main factor inducing the instability of the accumulation slope of the underlying layer.The scale of the disease has even exceeded the scale of the disease caused by other factors.Therefore,it is of great theoretical and practical significance to study the influence of highway construction project loading on the mechanical properties of accumulation slope subgrade in southwest mountainous area,as well as the disaster mechanism,disaster characteristics,failure mode and prevention countermeasures of accumulation slope subgrade.With the support of Chongqing Natural Science Foundation Project and Chongqing Traffic Science and Technology Project,the project is based on the project of ’Yuxiang Expressway Double Line(Banan to Pengshui Section)Wulong South Interchange Road Landslide Treatment Project ’.With the help of finite element numerical simulation and field demonstration test,the deformation and failure process of complex accumulation slope subgrade in subgrade filling process is systematically studied.After simulation and comparison of multiple schemes,a better treatment technology is proposed.The main research results are as follows :(1)Taking the large-scale complex accumulation body of Wulong South Interchange as an example,through data collection,on-site survey,drilling test and other means,combined with the development of cracks in the landslide area,the main sliding direction of the slope and the characteristics of the disease,the large-scale accumulation body slope is optimized into landslide area I and landslide area II.(2)According to the geological and slope deformation characteristics of the landslide area,the shear strength parameters of the soil are obtained through the inversion analysis of the typical profile of the landslide.The limit equilibrium method is used to select the typical profile and analyze the stability of each potential sliding surface.At the same time,the finite difference software FLAC 3D was used to simulate the instability mechanism and deformation failure process of the deposit slope under natural conditions and rainstorm conditions during the roadbed filling process.The calculation results are consistent with the field situation,which verifies the feasibility of the partition study of large complex accumulation landslide.(3)On the basis of identifying the engineering geological and hydrogeological environment of the large complex accumulation slope,combined with its deformation and instability characteristics,a sub-regional multiple treatment scheme is proposed.At the same time,considering the convenience of engineering economy and construction,through the in-depth study of the residual sliding force of landslide in each section,the selection method of the optimal retaining position of anti-slide pile is put forward to reduce the engineering cost and reduce the safety risk of pile excavation.The treatment scheme has been applied in field construction,which is economical and convenient,and verifies the reliability of the zoning treatment scheme of accumulation landslide.