某深基坑工程桩锚支护数值分析

Numerical analysis of a pile-anchor retaining structure of deep foundation pit engineering

依托唐山某深基坑工程,考虑桩锚土之间的相互作用,采用有限差分数值分析软件FLAC^3D模拟分析了土压力、桩身位移和弯矩随开挖进程的变化规律,以及锚杆倾角和桩嵌固深度对坑壁土体侧向位移的影响。研究结果表明：开挖结束后,桩身最大水平位移和桩身正弯矩最大值均出现在0.85 H（H为开挖深度）处,负弯矩最大值出现在1.3 H处;桩长范围内主、被动土压力最大值均出现在1.3 H处,而不是桩底;桩嵌固深度为0.5 H时,即可满足变形控制和基坑整体稳定性要求,锚杆倾角宜取为5°~25°,且不宜超过30°。

Based on a deep foundation pit engineering of Tangshan,considering the interaction of pile-anchor-soil,the finite difference software FLAC^3D is adopted in this paper to simulate and analyze the effect of dip angle of anchor and the embedded depth of pile on the horizontal displacement and the variation laws of earth pressure, horizontal displacement of pile with the process of excavation. The results show that the maximum value of horizontal displacement and positive moment of pile appear in 0.85H （H stands for the depth of excavation） and the negative moment appears in 1.3H after the excavation;the maximum value of active and pas- sive earth pressure appears in 1.3H rather than the bottom in the range of pile length; the re- quirements of deformation control and overall stability of foundation pit can be satisfied with 0.5H which is the embedded depth of the pile,and the dip angle of anchor is appropriate when it ranges from 5°to 25° but less than 30°.