基坑支护桩间土体拱效应理论及有限元分析

Soil arching between protecting piles of foundation pits and FEM analysis

深基坑支护桩间土体拱效应是在支护桩后一定范围内的土体上产生的。在此基础上,推导了考虑土拱效应的桩间土体承担的水平侧向土压力理论计算公式,并对土拱效应的主要影响因素——支护桩间距和土体力学性质,进行灵敏性分析。结果表明:桩间土拱效应主要发生在支护桩后2.5倍桩间土宽度范围内。最后,将深基坑支护桩间土体拱效应分析简化为平面问题,通过有限元数值分析探讨了土拱效应形成机理,理论计算与数值分析结果较为一致。

The previous researches drew the conclusion that the soil arching between protecting piles of foundation pits generates in the rather large domain behind the protecting piles. On such a basis, the pressure calculation formula bore by the soils between piles was deduced, and the affecting factors to the soil arching, for example, the space length between piles and the mechanical characteristics of soils were analyzed. The results show that the soil arching occurs at the scope of 2.5 times the width between piles behind the piles. Finally, the soil arching between piles was simplified to a plane problem, and it was studied by use of FEM. The results of theoretical and numerical analysis are in good agreement.