某住宅楼基坑支护FLAC3D数值模拟分析

Numerical simulation analysis of foundation pit support in a residential building using FLAC3D

为探索某基坑在开挖支护过程中的变形规律,把基坑开挖支护这一不可逆过程运用FLAC3D数值模拟软件将其可视化。通过分析基坑外地表沉降、坑内土体隆起和基坑侧壁水平位移的表现规律,分析基坑支护的稳定性、支护方案的可行性。随基坑开挖,桩后土体沉降的最大值出现在距基坑约12 m处,当基坑开挖至-3.5 m时沉降量明显较小;基坑隆起量、隆起速率有随基坑开挖深度增加而增大的趋势,开挖至-5.4 m时隆起速率最大,隆起量亦最大为15.4 mm。三次开挖过程中,基坑侧壁水平位移变形规律基本一致,开挖结束后最大水平位移出现在-3.85 m处,约为总开挖深度的三分之二。本基坑的各项变形指标模拟值均在可控以及规范要求范围之内,各分步开挖完成后,基坑变形规律基本一致。

In order to explore the deformation law of a foundation pit in excavation and support engineering,the irreversible process of foundation pit excavation and support is visualized by FLAC3D numerical simulation software. By analyzing the ground surface settlement outside the pit,the uplift of the soil in the pit and the lateral displacement of the foundation pit,the stability of the pit support and the feasibility of the support scheme are analyzed. With the excavation of the foundation pit,the maximum settlement of the soil behind the pile appears at about 12 m from the foundation pit. When the foundation pit is excavated to -3. 5 m,the settlement amount is obviously smaller; the amount of uplift and uplift of the foundation pit varies with the foundation. The pit excavation depth increases and increases. The excavation to -5. 4 m results in the highest uplift rate and the maximum amount of uplift is 15. 4 mm. In the third excavation process,the lateral displacement deformation laws of the sidewalls of the foundation pit are basically the same,and the maximum horizontal displacement after the ex-cavation is at -3. 85 m,which is about two-thirds of the total excavation depth. The simulation values of each deformation index of the foundation pit are within the scope of controllable and standard requirements. After each step excavation is completed,the deformation law of the foundation pit is basically the same.