路堑边坡预应力桩锚组合支护结构的变形特性分析

Analysis of Deformation Characteristics of Prestressed Pile-anchor Combined Retaining Structure Supporing a Cutting Slope

以某公路路堑边坡预应力桩锚组合支护结构为研究对象,对预应力桩锚支护结构的变形特性进行全施工过程现场监测,获得了施工过程中桩顶侧向位移和桩后土体水平位移随时间和空间的变化规律。采用FLAC3D软件对边坡开挖过程中的支护结构变形进行计算分析,将计算结果与现场监测结果进行对比,对开挖过程中坡顶和坡底的土体竖向位移分布规律进行了研究。研究表明:预应力锚杆对桩顶水平位移和桩后土体水平位移有良好的控制作用,开挖过程中的土体水平位移呈现着坡顶与坡脚小、中间部分大的趋势,土体水平位移的增长主要发生在开挖的中期。开挖过程中的桩顶水平位移、深层土体水平位移、坡顶土体竖向位移及坡底土体竖向位移均在合理的范围内。预应力的大小会对桩锚支护结构的支护效果产生影响,设置适当的预应力可有效减小支护结构的变形。

Based on the cutting slope of a highway,this paper conducts on-site monitoring of the deformation characteristics of the cutting slope combined prestressed pile-anchor supporting structure.Therefore,this paper obtains the law of the lateral displacement of the pile top and the horizontal displacement of the soil behind the pile with time and space during the construction process.FLAC3D software is used to calculate and analyze the deformation of the supporting structure during the slope excavation.The calculated results are compared with the field monitoring results,and the vertical displacement distribution of soil at the top and bottom of the slope during the excavation is studied.The analysis results show that the prestressed anchor has a certain restraint effect on the horizontal displacement of the pile top and the horizontal displacement of the soil behind the pile.During the excavation process,the horizontal displacement of the soil presents a tendency to be smaller at the top and toe of the slope,and larger at the middle part.The increase in the horizontal displacement of the soil mainly occurs in the middle of the excavation.During the excavation process,the horizontal displacements of pile top,deep soil,vertical displacements of slope top and bottom soil are all in reasonable range.The size of the prestress will affect the supporting effect of the pile-anchor supporting structure,and setting the appropriate prestress can effectively reduce the deformation of the supporting structure.