预留土基坑支护性状的有限元分析

应用小应变硬化土本构模型对郑州典型粉土地层中的预留土支护基坑的支护性状进行有限元分析,探讨预留土形状参数——顶部宽度、底部宽度等对基坑支护体系变形以及支护桩墙最大弯矩等的影响规律。借助强度折减有限元技术对各工况下支护体系的稳定性进行分析,通过分析强度折减安全系数,支护体系整体失稳与预留土局部失稳的先后关系等,揭示预留土形状参数对基坑支护性状影响的内在原因。并基于有限元计算结果对其它文献中的论断进行研判,分析其正确性和适用范围。分析结论对今后预留土支护基坑的设计以及优化设计颇具指导意义。

Retaining traits of berm-retained excavations by FEM

Based on the model for hardening soils with small-strain stiffness, the retaining traits of the berm-supported excavations in silt in Zhengzhou are studied by means of the finite element method. The influences of the berm shape, including the top width and bottom width of berms, on the retaining traits of the retained excavations, such as the maximum horizontal displacement and the maximum bending moment, are studied by analyzing the finite element results. The strength reduction method is employed to deduce the stability of the berm-retained excavations. The laws of influences of berm shape on the retaining traits are studied by analyzing the safety factor obtained by the strength reduction method. Some arguments obtained by the finite element method in available literatures are evaluated by the results obtained here. The conclusions may provide valuable guidance for the design and optimization of embedded retaining walls using earth berms as temporary supports.