多层桩锚支护深基坑开挖全过程数值模拟

Overall-process Numerical Simulation of Deep Foundation Pit Excavation Supported by Multi-layer Piles and Anchors

摘要:

为更直观地得到桩锚支护基坑在开挖过程中的变形和受力特征，并反馈于实际设计与施工，以珠海市某桩锚支护深基坑工程为例，基于有限差分软件FLAC3D建立精细化数值模型，计算分析各工况下基坑的变形和受力特性。分析结果表明：随着基坑开挖的进行，坑顶地表沉降量逐渐增大，最大地表沉降出现在距桩顶28 m的位置；坑顶地表沉降增速慢，表明预应力锚索的加入对于限制基坑变形具有较好的效果；锚索所需提供的抗拔力随开挖而逐渐增大，且第一级锚索所需提供的抗拔力最大，其次是第三级锚索；使用所建数值模型分析该基坑开挖过程是合理的，计算结果可为实际施工和设计提供参考。

Abstract:

In order to get the deformation and stress characteristics of the pile-anchor supported foundation pit during the excavation more intuitively and feed back to the actual design and construction, taking a pile-anchor supported deep foundation pit project in Zhuhai as an example, a refined numerical model is established based on the finite difference software FLAC3D to calculate and analyze the deformation and stress characteristics of the foundation pit under various working conditions. The analysis results show that with the excavation of the foundation pit, the ground surface settlement at the top of the pit gradually increases, and the maximum surface settlement occurs at the position 28 m away from the pile top. The slow increase of ground surface settlement at the top of the pit indicates that the addition of prestressed anchor cables has a good effect on limiting the deformation of the foundation pit. The pullout resistance required by the anchor cable gradually increases with the excavation, and the pullout resistance required by the first level anchor cable is the largest, followed by the third level anchor cable. It is reasonable to use the established numerical model to analyze the excavation process of the foundation pit. The calculation results can provide reference for the actual construction and design.