可回收桩锚支护基坑模型试验及数值模拟研究

Model Test and Numerical Simulation of Recoverable Pile-anchor Supported Foundation Pit

通过室内可回收桩锚支护基坑模型试验与数值模拟探究基坑施工全过程对支护结构变形的影响规律。结果表明:地表沉降曲线呈凹槽形分布,坑后1倍开挖深度范围内沉降变形受施工影响显著。坑底最大隆起变形最终发生于坑壁附近,坑底以下1倍开挖深度范围土体隆起变形明显为强影响区。在回填过程中,坑后0.75 H附近地表对沉降变形尤为敏感,增长幅度达54.5%。锚杆的失效回收是导致支护结构在回填阶段变形增长的主要因素,其中又以上层锚杆的影响最为突出。在采用可回收桩锚的工程中,基坑设计应统筹基坑开挖与锚杆回收这2个阶段。

Based on the model test and numerical simulation of foundation pit supported by recoverable pile and anchor,the influence law of foundation pit construction process on the deformation of supporting structure was explored.The results show that the surface settlement curve is groove-shaped,and the settlement deformation in the range of 1time excavation depth behind the pit is significantly affected by construction.The maximum uplift deformation at the bottom of the pit finally occurs near the pit wall,and the soil uplift deformation in the range of 1excavation depth below the pit bottom is obviously a strong influence area.In the process of backfilling,the ground surface near the pit 0.75 His particularly sensitive to settlement and deformation,with the increase rate of 54.5%.The failure recovery of anchor is the main factor leading to the deformation growth of supporting structure in backfill stage,among which the influence of upper anchor is the most prominent.In the project of adopting recoverable pile anchor,the foundation pit design should coordinate the two stages of foundation pit excavation and anchor recovery.