Analysis Of The Development Characteristics And Stability Of Landslides In The Weiyu Highway

With the implement of West Development Strategy,the highway mileage has grew significantly in western area improving road network structure,strengthening regional economy and improving transport environment so as to promote local economy development and society progress.However in recent years,the negative effect of highway is increasing day by day in western area.Geological disasters like landslide and collapse cause different degree of harm for traffic project construction,highway safety operation and regional people’s property security;therefore,the research of highway geological disasters has important significance.This thesis takes 25 landslides along WeiYu expressway as a research object,analyzes their growth characteristics,influence factor and formation mechanism to evaluate stability,and gets the following conclusion.(1)Growth characteristics of the landslide along WeiYu expressway.Analyzing from landslide thickness,scale,formation age and substance component,medium-bed landslide is developed,middle-sized landslide is in the majority and the new landslide is mostly primary dividing into Loess Landslide in layers and Loess Bedrock Landslide.Plane modality had four types including the fan-shaped,the ligulate,the imbricate and the M-shaped with double-ended.The profile morphology of Loess Landslide in layers is concave and Loess Bedrock Landslide is stair-step.External physical characteristic of ratio of the length of landslide width is mostly 1-1.6.The outlet position of boundary characteristic of Loess Landslide in layers is relatively high,while that of Loess Bedrock Landslide is relatively low.The back of slip band of deformation characteristic Loess Landslide present approximately linear but that of Loess Bedrock Landslide present the circular shape.The motion characteristic of Loess Landslide is collapse-type primarily,and that of Loess Bedrock Landslide is diastrophic sliding-put.(2)Influence factors of the landslide growth along WeiYu expressway.The major factors are atmospheric precipitation,degree of landslide,surface water and formation lithology.The secondary major factors are height of landslide,engineering construction,underground water,geomorphology,new neotectonic movement,agricultural irrigation,structural framework,exterior load and breakage.Formation reason of the landslide along WeiYu expressway.Formation lithology is the important endopathic cause and material basis.Topography is the space factor of landslide formation.Rainwater is the most active dynamic factor and inducing factor.Creep and crack movement mechanism is put forward including four stages which are creep deformation,peristalsis extrusion,sliding acceleration and tensile fracture.(3)Stability evaluation of the landslide along WeiYu expressway.Loess Landslide is in basically stable state under the condition of gravity and in primarily unstable state under the condition of gravity and rainstorm.Rainfall makes the stability coefficient of landslide along WeiYu expressway decrease by 8.23%.Earthquake makes the stability coefficient of landslide along WeiYu expressway decrease by 8.23%.Research area is divided into stable-basically stable area and understable area.