含厚软弱夹层地基上桩基础沉桩特性数值分析

发布时间：2018-05-25 08:02

本文选题：圆孔扩张理论 + 有限单元法　；参考：《东北大学》2013年硕士论文

【摘要】：随着我国沿海地区工程建设规模的不断扩大,土木工程建设中,遇到的大量复杂的不良地基和地基处理问题也越来越多,人们也越来越重视地基处理问题。由于钢筋混凝土预制桩的坚固耐久、能承受较大荷载、机械化程度高、进度快、能适应不同土层施工等优点使它成为我国目前广泛采用的一种桩基础地基处理方式。由于在打桩过程中,会不可避免地产生挤土位移,对周围建筑物和已完成桩体造成一定的影响,而广泛受到岩土工程界的关心。本文开始较为详尽罗列了国内外关于研究沉桩挤土的试验研究与理论方法,包括圆孔扩张理论、土的抗剪强度理论以及桩基承载力理论。在此基础上,结合大连万科海港城一期项目工程,研究考虑桩土相互作用及位移贯入的有限单元法。通过介绍大型有限元软件ABAQUS在岩土工程中的适用性及优点,具有强大的接触面处理功能,能够很好地处理大变形、大位移和桩-土接触等问题。使用土的Mohr-Coulomb模型,对桩的连续贯入过程进行了模拟；通过模拟结果分析了预制桩在压入不同深度土体时的水平和竖向位移变化。最后,结合工程实例,分析研究了减小挤土位移影响的方法与理论,并对采取置换填土法、预钻孔法措施前后进行了模拟与比较分析,得出了置换填土和预钻孔法可以有效的减小沉桩对周边土体与桩体的挤土影响。另外还提出了防挤沟、砂井排水、合理安排施工顺序、信息化施工等其他控制措施。
[Abstract]:With the continuous expansion of the scale of engineering construction in coastal areas of China, a large number of complex problems of poor foundation and foundation treatment are encountered in civil engineering construction, and people pay more and more attention to the problem of foundation treatment. Because of its strong durability, large load, high mechanization, rapid progress, and so on, reinforced concrete prefabricated pile has become a widely used method of pile foundation treatment in our country at present. In the process of piling, the displacement of compaction will inevitably occur, which will have a certain influence on the surrounding buildings and the completed pile body, and has been widely concerned by the geotechnical engineering community. In this paper, the experimental and theoretical methods for studying pile-driven soil are listed in detail, including the theory of circular hole expansion, the shear strength theory of soil and the theory of bearing capacity of pile foundation. On this basis, the finite element method considering pile-soil interaction and displacement penetration is studied in the first phase project of Dalian Vanke Port City. By introducing the applicability and advantages of large-scale finite element software ABAQUS in geotechnical engineering, it has strong contact surface treatment function and can deal with large deformation, large displacement and pile-soil contact problems. The Mohr-Coulomb model of soil is used to simulate the continuous penetration of the pile, and the horizontal and vertical displacement changes of the precast pile under different soil depths are analyzed by the simulation results. Finally, combined with engineering examples, the methods and theories of reducing the influence of squeezing displacement are analyzed, and the simulation and comparative analysis before and after adopting displacement fill method and pre-drilling method are carried out. It is concluded that displacement fill and pre-drilling method can effectively reduce the influence of piling on the surrounding soil and pile body. In addition, other control measures such as anti-squeezing ditch, sand well drainage, reasonable arrangement of construction sequence, information construction and so on are put forward.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU473.1;TU433

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