Stability Evaluation And Control Effect Of Futang Landslide In Hanyuan County

The Futang landslide is located in the northwest of the construction site of Hanyuan new county,there is a crack-creep phenomenon at the back of the slope,the slope may undergo deformation and slippage during the construction and subsequent operation period,which is extremely unfavorable to the engineering construction and the safety of buildings.Based on the monitoring results of landslide engineering geological conditions,slope deformation characteristics and sliding surface characteristics,this paper analyzes the influence factors and formation mechanism of slope deformation and failure with geological analysis methods.Then,the limit equilibrium method and ABAQUS numerical simulation are used to analyzed the stability,deformation trend and distribution of plastic zone when the slope before and after excavation.Finally,ABAQUS numerical simulation and field monitoring results are used to comprehensively evaluate the treatment effect of landslide,by analyzing the slope body surface displacement,deep displacement,stability change and earth pressure of retaining measures.The main contents and results are listed as follows:(1)The landslide area is in an irregular"long bow shape"on the plane,with a total square volume of about 3.17×106 m~3.The underlying bedrock is Triassic Baiguowan Formation sandstone.There are multiple weak interlayers and two sets of mutually perpendicular steep dip joints in the rock mass,and some weak interlayers form a sliding surfaces.Different thickness of residual blocks and gravels of previous landslides are accumulated on the front edge of the slope,and the phenomenon of deformation and tension-fracture generally exists in the rock mass at rear edge and both sides.The deformation and failure of landslides are mainly affected by terrain landform,stratigraphic lithology,geological structure and precipitation.The failure mode is slippage-tension fracture,and the main triggering factor is precipitation,which belongs to gently lnclined bedding rock push landslide.(2)The results of stability analysis show that the slope before excavation is in an unstable state under the extreme condition of natural+rainstorm+earthquake,and is basically stable to stable under other conditions.After the excavation,the slope is in a unstable state under natural+rainstorm+earthquake condition and natural+load+rainstorm+earthquake condition,the slope is in a basically state under natural+load+rainstorm condition and in a not enough to basically state under natural+load+earthquake condition,stable under other conditions.which lead to insufficient safety reserves,the anti-slide piles and retaining walls are used to reinforce the slope during the construction.(3)The numerical simulation results show that the slope mainly slides integrally along the transfixion weak interlayer,and the rear part of the slope is prone to form a cracked plastic zone,which is the same as the slope slippage-tension fracture failure mode.(4)After slope treatment,the numerical simulation results and monitoring data analysis show that the numerical simulation is consistent with the monitoring results.but the calculation results of retaining measures deformation,earth pressure and slope deformation by the two methods all meet the design standards.Therefore,it can be comprehensively judged that the deformation and plastic strain of the slope have been controlled effectively by the treatment measures,the stability factor of the slope has increased significantly,the retaining measures deformation,earth pressure and slope deformation all meet the design standards,the slope is overall stable under various conditions.