Stability Analysis And Control Measures Of Jinqiao Landslide On Suining-Guang'an Expressway

The red-bed area is widely distributed in China,and it is easy to induce landslide due to its rock and soil properties and particularity of rock structure.The near-horizontal stratified rock slope has a small dip angle,which causes incalculable loss to life and property.The jinqiao landslide on the right side of section CK0+447?CK0+673 of Suining to Guang'an expressway is located in the middle of Sichuan basin,the main red-bed distribution area in China.The rock stratum has a small dip Angle,and the internal stress balance is disturbed to form a landslide due to the influence of highway excavation,which hindering the highway construction and causing hazards for the normal operation of expressway in the future.Therefore,in this article,through the field reconnaissance,drilling,such as surveying and mapping technology to Jinqiao the boundary of the landslide,rock mass structure,stratum lithology and other basic geological conditions,and analysis platform by FLAC^3D,the Jinqiao landslide in natural and rain change characteristics of two kinds of working conditions,in order to avoid the subjectivity of qualitative analysis and quantitative analysis of excessive dependence on the calculation model combining qualitative analysis with quantitative analysis,the mutual authentication,overall judgment jinqiao landslide stability state,on this basis puts forward reasonable prevention and control measures.The research results provide a typical case for the near-horizontal stratified rock landslide in the construction of expressway in China,and have important reference value for the prevention and control of jinqiao landslide,and can effectively reduce the loss caused by the landslide.Specific research results are as follows:(1)Through field investigation shows jinqiao landslide occurred in sichuan red bed region nearly horizontal bedded rock landslide,the landslide as a whole"slow down the steep terrain,it is on the floor plan round-backed armchair,the volume is about 301104 m³,the lithology from top to bottom respectively quaternary floated pebble alluvium and silty mudstone in suining group,on both sides of the slope can be observed from the downward development of weak intercalations,slope at the front of the deformation and failure at the back of the slope deformation and failure is obvious.(2)Golden bridge of the landslide affected by internal and external force are common in dynamic action is the basis of landslide,landform,stratum lithology,geological structure analysis,three factors outside dynamic action is landslide induced condition,selection of rainfall and human engineering activities analysis,two factors that several factors create unfavorable geometric conditions of landform,stratum lithology provides good permeable channels,rainfall and highway excavation is inducing factors of landslide instability.Based on the analysis of deformation characteristics of jinqiao landslide,it can be known that the deformation failure mode of jinqiao landslide is"slip-pull-crack-shear".(3)Combined with the study of regional geological environment data,FLAC3D software was used to calculate and analyze the impact of highway excavation on the deformation and failure rules of the landslide,and the mechanics and displacement characteristics of the slope under natural and rainstorm conditions were simulated.The results show that under natural working conditions,the stability of jinqiao landslide is reduced by the influence of highway construction,the mechanical strength of the weak structural plane of jinqiao landslide is reduced by rainfall,and the deformation of the slope is intensified.(4)By comprehensively analyzing the results of qualitative evaluation and quantitative calculation,the following conclusions are obtained:under natural conditions,the stable state of Jinqiao landslide is less stable?basically stable;when it rains,the stable state of Jinqiao landslide is unstable.The following conclusions can be drawn from the comprehensive analysis of the results of qualitative evaluation and quantitative analysis:under the natural working conditions,the stable state of jinqiao landslide is under-stable?basically stable;Under the condition of rainstorm,the stable state of jinqiao landslide is unstable.(5)Three prevention and control measures were proposed according to the results of numerical simulation and landslide stability research.After comparative analysis,"slope cutting+anchor+retaining wall"was selected as the best plan.