Research On Stability Analysis And Prevention Measures Of Slope In Xiangshan Area Of Beijing

There are many mountainous landforms in China,and the construction of natural slopes and artificial slopes is frequent.Natural slopes and artificial slopes are numerous in nature and cities.Small and medium-sized slopes are often neglected because of their small scale and large number.In order to save money,Slopes are often simply supported by masonry retaining walls,lacking accurate geotechnical calculation and professional support design.A small and medium-sized slope in Xiying Village,Xiangshan District,Beijing,is located in residential area.Human engineering activities are complex.On July 17,2015,affected by continuous rainfall scouring,the surface soil of the slope is collapsed on a small scale.There were two rows of walls at the foot of the original slope.Because of unreasonable support design,the first retaining wall in the upper part of the rainfall slipped outward,and some of the walls were staggered broken,with the maximum staggered distance of 12cm.In this paper,GeoStudio is used to simulate the slope by fluid-solid coupling method and analyse slope stability Change under Rainfall.According to the simulation results,the slope stability factor is 1.28 in natural state and 1.23 under rainfall.There has the possibility of secondary failure in severe rainfall surroundings,so support design is needed.Considering that the slope is located in residential area,and Buildings are under construction or to be built on top of slopes,from a long-term point of view,this paper adopted the composite support form of anchor lattice beam,which integrated deep and shallow supports,and has high reserve.It could also plant greening and improve the environment.In this paper,FLAC~3DD is used to simulate the supporting effect.The stress and strain states of the slope are studied by applying three kinds of loads:10kN/m~2,30kN/m~2 and 50kN/m~2 on the top of the slope.It was found that the deformation of the average slope body was very small and stable,which proved that the design scheme was safe and reliable.Through this study,the following conclusions were drawn:(1)Through fluid-solid coupling simulation,it was found that because of the low permeability of silty clay,rainwater could not effectively infiltrate under strong rainfall conditions.Although the stability of slope was reduced,the range is limited.Combining with the failure form of slope body,it can be concluded that on July 17,2015,slope failure was mainly due to erosion of slope body which intensified rainwater infiltration and destroyed the stability of slope body,so it is necessary to focus on the slope protection treatment.(2)Slope stability gradually decreases under rainfall,and reaches the minimum after rain.At the same time pore pressure dissipates and stability rises slightly with rain seepage.(3)The anchor lattice beam composite support has reliable supporting effect and high safety reserve.When the load is applied on the top of the slope,the deformation is very small and the slope body can be maintained stable.(4)When the upper load increases,the vertical displacement of the top of the slope decreased from the breaking inside to the free side under the influence of anchorage force,and the horizontal displacement of the slope increased gradually from the top to the foot of the slope.Considering from the angle of support,the length of the anchor rod at the foot of the slope can be increased appropriately and the stability of the slope can be improved.