深基坑疏桩强锚支护结构参数敏感性分析

依托西安幸福林带基坑工程，通过采用ABAQUS有限元软件建立基坑三维数值模型，研究了桩距桩径比对支护结构内力和变形的影响；对影响支护结构内力与变形的各个支护参数进行了敏感性分析，并且基于此设计了正交实验，提出了依托工程的疏桩强锚优化设计。得出结论如下：（1）支护桩身内力及支护结构顶部水平位移随支护桩距桩径比值的增大而增加，并且桩距桩径比值的变化对桩身下半段内力以及基坑开挖后半段变形的影响较为显著。（2）支护参数敏感性分析表明：支护参数对支护结构内力与变形敏感性强弱顺序依次为：支护桩距径比>锚索预应力>锚索竖向间距>锚索长度>锚索安置倾角。（3）基于支护参数敏感性分析，对当前工程背景下疏桩强锚支护结构进行优化，为类似工程提供参考。

Sensitivity analysis on parameters of sparse pile and strong anchor supporting structure for deep foundation pit

Based on the Xi''an XingFuLinDai Foundation pit Project, a three-dimensional numerical model of the foundation pit is established by ABAQUS finite element software in this paper.The influence of pile distance to pile diameter ratio on the internal force and deformation of the supporting structure is studied; the sensitivity analysis of each supporting parameter that affects the internal force and deformation of the supporting structure is carried out, and an orthogonal experiment is designed based on this, the optimized design of sparse piles and strong anchors based on the project is proposed. The conclusions are as follows: (1) As pile distance to pile diameter ratio increases, the internal force of the supporting pile and the horizontal displacement of the top of the supporting structure also increase, and the change in the pile distance to pile diameter ratio affects the lower half of the pile. The influence of internal force and the deformation of the second half of the excavation of the foundation pit is more significant. (2) The sensitivity analysis of supporting parameters shows that the order of the sensitivity of supporting parameters to the internal force and deformation of the supporting structure is as follows: supporting pile distance-diameter ratio> anchor cable prestress> anchor cable vertical spacing> anchor cable length >The inclination angle of the anchor cable placement. (3) Based on the sensitivity analysis of support parameters, the sparse pile and strong anchor support structure under the current engineering background is optimized, and it could provide reference for similar projects.