车辆超载作用下软弱基坑变形特性研究

作用于坑顶的车辆荷载对于软弱基坑的变形和稳定具有重要影响,甚至可能成为相应的控制条件。本文基于珠江三角洲地区软弱基坑的一般特征,根据现行规范和已有研究成果,系统分析了坑顶车辆超载的计算模型和坑周土的本构模型,针对车辆荷载的拟静力单轴模型和土的修正剑桥模型建立了有限元计算模型,通过一个算例计算了坑顶车辆荷载作用下基坑在开挖与支护过程中坑周土体的变形规律和基坑的失稳特征,并进一步分析了坑顶车辆动载的影响深度及土的本构模型参数对变形规律的影响。结果表明,所选取的车辆计算模型和土的本构模型可以用于实际工程,计算结果可对支护结构的设计提供指导。

Research on Deformation of Foundation Pit in Soft Clay under Vehicle Overloads

Vehicle overload has important influence on the deformation and failure of foundation pit in soft clays, which even is a control condition in some practical enginerring. In the light of the engineering characteristics of soft foundation pit in the Pearl River Delta region and currently China National Standards, the calculation models of vehicle overload and constitutive model of soils around the pit are analyzed in this study. By means of pseudo-static concentrated load model of vehicle overload and modified Cambridge Clay model of soils around the pit, the plane FEM for a foundation pit is established. The deformation regularity and unstability feature under vehicle overload are analyzed, with excavating and pit-bracing, and the further analysis for the effect of vehicle overload on foundation pit and the parameters sensitivity of Cambridge model has been done. The results show that the models of vehicle overload and constitutive relationship of soils are applicable for practical engineering, which can guide the design of supporting structure.