主裙楼一体结构的地基承载力理论与试验研究

With the development of urban construction, more and more high-rise buildings and large public buildings are constructing，and large number of them are the mainbody structure with annexe building.The foundation of such buildings embedded deeply as well as the impact of the annexe building, the traditional theory is not available for the bearing capacity of mainbody structure foundation. In this project, bearing capacity of mainbody structure with annexe building is simplified as effect of embedded depth and surcharge on bearing capacity. The behavior of design theory of bearing capacity with embedded depth and surcharge will be investigated systematically by analytical method, numerical simulation and model test. Our program mainly focuses on the following topics: (1)establish elastoplastic solution fully consider effect of embedded depth and surcharge with limited distribution width; (2)numerical simulation of the foundation bearing capacity under different depths, asymmetric overload, limited distribution overload conditions; simulate numerically bearing capacity under a series of complex conditions,such as various embedded depth, asymmetric overload and surcharge with limited distribution width;(3)reveals the bearing behavior of foundation with embedde depth and surcharge and verify the results of theoretical analysis by model tests;(4) establish bearing capacity factors for engineer by investigating a large number of parameters. The research of this program not only has an important value of academic and engineering practice, but also broad application prospects.

随着城市建设的发展，高层建筑和大型公共建筑大量兴建，大量存在着主裙楼一体结构。这类建筑的基础埋置较深以及有裙楼的影响，其主体结构的地基承载力确定对传统的承载力理论提出了新的挑战。本项目将有裙楼的主体结构地基承载力简化为有埋深与超载的地基承载力课题，拟通过解析法、数值模拟和室内模型试验，系统地研究有埋深与超载的地基承载性状及其设计计算理论。具体内容包括：建立能充分考虑基础埋深及有限分布宽度超载影响的地基承载力弹塑性解；对不同埋深、非对称超载，有限分布超载等复杂条件下的地基承载力进行数值模拟；采用室内模型试验揭示有埋深和超载的地基承载性状，验证理论分析成果；通过大量参数分析，建立便于工程技术人员应用的地基承载力修正系数表格。本课题的研究不仅具有重要的学术和工程实践价值，更具有广阔的应用前景。

目前建筑工程大量存在着主裙楼一体的结构，对于主体结构地基承载力的深度修正尚无深入的研究。规范（GB50007）建议采用简化算法，即将基础地面以上范围内的荷载按基础两侧的超载考虑，当基础两侧超载不等时，取小值。这一简化算法的准确性或误差的定量性研究未见报道。本项目针对主裙楼一体的结构的主体结构地基承载力问题，采用解析法、模型试验以及数值模拟进行了研究。项目的主要的研究内容及成果如下：（1）推导了非对称超载条件下的地基临界荷载。在非对称超载和地基临界荷载的作用下，地基塑性区和对称超载情况下塑性区的分布有明显的不同。此部分的研究表明，考虑非对称超载的影响的地基临界荷载和简化算法的计算结果差异较小，基本可以忽略不计，该计算结果定量的验证了规范中简化算法的准确性。（2）采用模型试验获得了砂土在非对称超载条件下的承载特征。此部分研究通过模型试验分析了非对称超载对地基极限荷载、地基应力分布、地基变形地基破坏模式的影响。（3）通过数值模拟分析了非对称超载对地基承载特性的影响。此部分研究通过数值模拟，获得了一种“理想化”的地基材料在非对称超载条件下的承载特性。