高层建筑深基坑工程数值分析及支护结构优化设计研究

【作者】 刘斌；

【导师】 章定国； 章杨松；

【作者基本信息】 南京理工大学 ， 固体力学， 2003， 硕士

【摘要】 本文对国内外与深基坑工程支护设计计算相关的问题进行了分析和总结。为本文之后的分步开挖的基坑平面有限元模拟分析和研究提供了参考和依据。 在考虑土与结构相互作用的基础上，采用二维平面有限元法建立了深基坑有限元模型，并模拟其复杂的分步开挖过程，对基坑性状的进行了分析和探讨。模型采用八结点等参平面四边形单元、Drucker-Prager理想弹塑性本构模型以及用接触面单元模拟了土与围护结构的相互作用，并给出了相应的接触面模拟的接触算法流程。 利用平面有限元模型对深基坑工程的开挖性状进行了分析，研究了开挖过程中围护结构的水平位移、墙后土体的地表沉降、支撑力等的分步开挖效应。探讨了围护结构刚度(墙体宽度)、墙体插入深度和支撑刚度对基坑性状的影响。 提出了基于变形控制的支护体系优化设计方法。该方法考虑了支护结构和土的相互作用；考虑了支护结构和内撑结构之间的整体协调。首次将优化技术和有限元方法相结合的方法，用于基坑支护体系的优化设计，结果显示出该方法是可行的。更多还原

【Abstract】 The computation methods and pertinent problems of the support works of deep excavation are analyzed and summarized in detail in this paper, which are the references to the FEM analysis of the multi-staged excavation.With the consideration of soil-structure interaction, process of multi-staged construction, A plane FEM model for simulating excavation is established, which is used to analyze and discuss the behaviors of excavation. The model adopts eight-nodes isoparametric quadrilateral element, Drucker-Prager ideal Elastic-Plastic stress-strain model and the contact element, which is used to simulate the interface between the wall and soil. Accordingly, A flow chart about the arithmetic of contact is introduced in this paper.The plane FEM model analyzes the behaviors of deep excavation, and the step-excavation effect during excavation is studied such as the horizontal displacement of the retaining wall, ground settlement and the forces in struts. The influences on the behaviors of excavation are discussed due to the stiffness (width) of the retaining wall, the embedded length of the wall and the strut stiffness.Based on the deformation control, optimization design method of the retaining structure is proposed. This method considers the interaction of soil-structure and the whole harmony of the retaining structure and inner-support structure. First the method combines optimization design method with FEM. The results of analysis prove that this method is feasible.更多还原