风化板岩地区基坑双排桩的数值模拟研究

Numerical Simulation of a Deep Excavation in Weathered Slate Area Supported by Double-Row-Piles

针对双排桩支护结构的变形与控制,采用有限元软件对风化板岩地区的基坑开挖施工进行数值模拟,对基坑开挖过程中基坑周边地表沉降、桩身水平位移和桩身内力进行了分析,并与现场实测结果进行了对比分析,为施工和设计的优化提供合理的建议。研究表明:在风化板岩地区的基坑开挖过程中,应对基坑周边6.5 m左右的地表沉降以及双排桩桩顶的水平位移进行重点监测;同时发现,前排桩在桩顶以下4.5 m和桩顶以下16 m处,后排桩在桩顶位置和桩顶以下16 m处均出现很大的弯矩,表明这些位置是在基坑施工过程中需要重点进行监测的部位。

The deformation of a double-row-piles supported deep excavation project in the weathered slate area was numerically simulated by using finite element method.The ground subsidence surrounding the excavated area,lateral deflection as well as the stress in the supporting structure during the entire excavation process were evaluated and compared with the construction monitoring data in order to provide an optimized excavation sequence.The results indicate that,in the excavation process in the weathered slate area,the ground settlement within a distance of 6.5 to the excavated area and lateral deflection at the top of double-row piles should be monitored with more attentions;Further,large bending moments were observed in the front row piles 4.5 mfrom the top and the and 16 mfrom the pile top in piles in the rear row.