Research On The Stability Of Loess Slope Under The Basic Action Of Slope Top Building In Dongshan,Taiyuan

Taiyuan is located in the central and eastern part of the Loess Plateau,and the seismic fortification intensity is 8 degrees.Due to the shortage of urban land,a large number of loess slope buildings are produced in Dongshan,Taiyuan,The building foundation load has an adverse impact on the deformation and stability of the slope,especially under earthquake conditions,resulting in excessive deformation and even instability of the slope.Therefore,it is of great theoretical and practical significance to speed up the research on the stability of loess slope under the basic action of slope top building in Dongshan,Taiyua.In this paper,the two-dimensional slope and building foundation analysis model is established by using Midas GTS NX finite element analysis software.By studying the influence of raft foundation and pile foundation under different loads and different slope top distance on the slope under static conditions and earthquake,the horizontal displacement,sliding surface position,slope stability safety factor and acceleration amplification effect of the slope are analyzed,and compared with the results of simplified Bishop method,The conclusions are as follows:(1)when the slope is in its natural state,the shape of the most dangerous slip surface of the strength reduction method and the simplified Bishop method is basically the same,both of which are arc-shaped.The finite element safety factor is greatly affected by the division of grid arrangement shape,with a difference of0.5%-6.8%.(2)Under the action of raft foundation load,the change trend of safety factor of strength reduction method is similar to that of simplified Bishop method,and the calculation result is slightly larger than that of simplified Bishop method due to the influence of grid characteristics.(3)When the distance is far and the load is small,the position of the sliding surface is the same as that of natural slope,and the slope is less affected by the load;When the load is large and the distance is close,the most dangerous slip surface passes through the corner of the affected area and the slope toe.(4)Under the action of pile foundation load,the soil within the pile foundation changes synchronously with the pile foundation,the plastic deformation area at the pile bottom develops significantly and tends to the slope toe.The pile length is large or the load is small,the pile foundation blocks the most dangerous sliding,develops towards the slope,and penetrates along the outer pile foundation to the slope top,which significantly improves the stability of the slope.(5)The acceleration of the slope is amplified in varying degrees.The amplification factor of the top of the natural slope is 1.258,and the occurrence time of the maximum peak value is delayed with the increase of the slope height.Under the action of foundation load,the amplification effect of raft foundation is less than that of pile foundation,and the amplification effect of pile foundation is less than that of natural slope.When the raft foundation is close to the slope top,the amplification factor changes rhythmically with the increase of load,and the maximum difference is 0.095.(6)Under the action of earthquake,the trend of safety factor and foundation load change curve for different calculation methods of raft foundation is basically the same.The quasi-static method of pile foundation is larger than the minimum average safety factor and larger than the minimum safety factor.Due to the blocking effect and curtain effect of the pile foundation,the pile foundation can improve the stability of the slope.(7)Comparing the influence of raft foundation and pile foundation on slope,the reduction effect of raft foundation on slope amplification effect is greater than that of pile foundation,and the influence of pile foundation on slope displacement is less than that of raft foundation.Pile foundation is better than raft foundation,and the pile length should not be less than 2/3 of the slope height.Pile foundation is more beneficial to slope stability than raft foundation.