Study On Slope Stability And Soil Arch Effect Of Anti Slide Pile Based On FLAC3D

With the rapid development of highway infrastructure in northwestern China,in the process of highway engineering construction,geological disasters such as the instability of the original slope and the resurgence of landslides are emerging one after another.The topic selected in this article is from the Qingjian-Zichang Expressway in Shaanxi Province,during the construction of this highway,due to the lack of preliminary survey work,it caused a loessbedrock slope instability during the excavation project.This paper will take the unstable slope as an example,and use RHINO built 3D modeling,FLAC3 D to simulate the excavation instability process of the slope and the analysis of the soil arching effect of the anti slide pile.The instability of the slope is mainly due to the exposure of mudstone caused by excavation,forming a rock soil interface prone to sliding.The deformation and failure of this section is the most serious,and the stability is relatively better than that of the other section without mudstone exposure,therefore,in the slope stability analysis process,focus on these two profiles from the principal stress,shear stress,displacement,shear strain increment and other aspects,finally,from the perspective of the three-dimensional model,the influence of the pile type and spacing of the anti-slide piles on the soil arch effect is analyzed.The main research results obtained in this paper are as follows:(1)The instability slope of Tuo jia gou is a mixed loess bedrock slope,on the spot investigation revealed that the excavation slope of this slope was severely damaged,with more cracks developed,and cracks also developed in the back and middle of the slope,indicating that the slope is currently Stability is extremely poor.(2)According to on-site investigation and drilling exploration,combined with the results of three-dimensional numerical simulation,on the one hand,the instability of this slope is due to the slope structure of the upper soil and lower rock,The strength parameter of the contact surface drops sharply under the condition of rainfall and water saturation.On the other hand,the mudstone is exposed due to construction excavation,and the stress distribution of the slope is severely damaged,the two factors mainly cause the instability of the slope.(3)Combined with the distribution characteristics of monitoring curves of many monitoring points distributed on the slope,it is found that the monitoring points with the largest deformation are mostly located in the mudstone outcropping zone in the middle of the slope,and gradually smaller to both sides,which also proves that the mudstone outcropping is not conducive to the stability of the slope;at the same time,it can be seen from the monitoring curve that the time period of sudden change of the monitoring curve basically coincides with the local rainfall time point,indicating that the slope It shows the deformation characteristics of "increasing sharply in case of rain".(4)Using RHINO software to complete complex three-dimensional geological modeling,make the simulation results more realistic,restore the distribution characteristics of stratum structure as much as possible,in order to analyze the deformation and failure characteristics of slope from the perspective of stratum distribution characteristics.(5)The influence of distributed excavation on slope stability is realized by FLAC3 D command flow,through numerical simulation: after the first and second stages of excavation are completed,the slope has no signs of deformation and destruction,whether in the natural state or in the saturated state;After the completion of the third stage of excavation,only in the natural state,there are signs of slope damage on the excavated slope,and there are also small cracks in the middle and front of the slope body,indicating that the slope stability is relatively poor,After the rainfall,the slope cracks developed rapidly under saturated water conditions and continued to the rear of the slope.Finally,a continuous crack was formed in the rear of the slope.(6)This paper analyzes and studies the influence of the size and spacing of anti slide piles on the distribution characteristics of soil arching effect,and makes a comparative analysis from three aspects: the distribution characteristics of principal stress,displacement and the increment distribution characteristics of shear strain.Finally,an optimal combination of anti slide piles is selected for the treatment and design of slope engineering according to the most reasonable and full use of the soil arching effect of anti slide piles.