深基坑桩锚支护位移及内力数值模拟分析

利用FLAC3D数值模拟软件,按照实际施工工序模拟基坑开挖支护全过程,得到了桩锚支护结构以及基坑外土体沉降和基坑侧壁水平位移随基坑开挖的变形规律:随基坑开挖深度的增加,基坑外土体沉降逐渐增大,变化曲线呈"勺状"分布;基坑顶和基坑侧壁水平位移随开挖深度增加均逐渐增大且都在开挖至基坑底时位移最大;桩身弯矩最大值处基本出现在基坑开挖深度1.5 m以上的位置,最大负弯矩值为76.7;锚索轴力最大位置出现在锚索的端头处,且从端头位置向端尾位置逐渐减小,而第1排至第3排锚索最大值逐渐增大,说明支护结构中第2、3排锚索起主要作用,验证了深基坑桩锚支护的可行性。

Numerical Simulation Analysis of Displacement and Internal Force of Pile Anchor Support in Deep Foundation Pit

By using FLAC3D numerical simulation software, the whole process of foundation pit excavation and support is simulated according to the actual construction procedure. The deformation law of pile-anchor supporting structure, the soil outside the foundation pit and the side wall of the foundation pit with the excavation is obtained. With the increase of excavation depth, the settlement of soil outside the foundation pit increases gradually, and the variation curve is "spoon-shaped". The horizontal displacement of the top and side wall of the foundation pit increases gradually with the excavation and reaches the maximum when they are all excavated to the bottom of the foundation pit. Maximum value of the bending moment of the pile basically appears at a position 1. 5 m above the current excavation depth of the foundation pit, and the maximum negative bending moment is 76. 7. The maximum position of the anchor cable axial force appears at the end of the anchor cable, and gradually decreases from the end position to the end tail position, and the maximum value of the first row to the third row anchor cable gradually increases. It shows that the second and third rows of anchor cables play a major role in the supporting structure, which verifies the feasibility of deep foundation pit anchor support.