单排抗滑桩支挡型黄土边坡坡脚基坑开挖诱发坡体滑动的演化过程研究

Study on the evolution process of slope sliding induced by foundation pit excavation of loess slope foot supported by single row anti-slide piles

坡体开挖是影响既有坡体安全稳定的重要因素之一,近年来出现了一些在坡脚处施作基坑的工程项目,虽已有研究对坡脚开挖诱发坡体滑动过程进行了分析,但是对于存在抗滑桩支挡结构的坡体,该过程仍未明确。依托一坡脚开挖基坑引起坡体滑动的工程实例,在ABAQUS中模拟了单排抗滑桩支挡型黄土边坡坡脚开挖诱发坡体滑动过程。结果表明:随着坡脚处土体开挖深度的逐渐增加,开挖区底部开始出现塑性区,并不断向坡体方向扩展。坡体的变形范围逐渐由开挖区底部向坡体方向扩展,抗滑桩下部土体逐渐陷落,到达一定开挖深度后,坡体出现局部滑动。这一破坏过程与形式与实际发生坡体滑动一致。在此类工程设计时,基坑围护结构沿坡体滑动方向的抗剪强度对基坑和坡体的安全稳定至关重要,应加强结构抗剪强度、充分验算每开挖进尺围护结构的抗剪承载力、缓慢开挖,防止作用在基坑围护结构上的剪应力骤然增加。

Slope excavation is one of the important factors affecting the safety and stability of the existing slope.In recent years,there have been some engineering projects that apply foundation pit at the slope toe.Although some studies have analyzed the slope sliding process induced by slope toe excavation,for the slope with anti-slide pile retaining structure,the process is still not clear.Based on an engineering example of slope sliding caused by excavation of a slope foot,this paper simulated the slope sliding process induced by excavation of slope foot supported by single-row anti-slide piles in ABAQUS.The results show that the plastic zone begins to appear at the bottom of the excavation area and continues to expand towards the slope with the increase of the excavation depth.The deformation range of the slope gradually expands from the bottom of the excavation area to the slope body,and the soil under the anti-slide pile gradually subsides.After reaching a certain excavation depth,the slope body appears local sliding.The failure process and form are consistent with the actual slope sliding.In this kind of engineering design,the shear strength of the foundation pit retaining structure along the slope sliding direction is very important to the safety and stability of the foundation pit and the slope.The shear strength of the structure should be strengthened,the shear bearing capacity of the retaining structure with each excavation step should be fully checked,and the shear stress on the foundation pit retaining structure should be slowly excavated to prevent the sudden increase of the shear stress on the foundation pit retaining structure.