强夯法施工参数对加固效果的影响及数值模拟研究

发布时间：2018-05-28 16:07

本文选题：强夯 + 施工参数　；参考：《石家庄经济学院》2013年硕士论文

【摘要】：强夯法是一种方便快捷、经济环保的地基处理方法。自问世以后，便很快在全世界流行开来。对于强夯法，最终的目标是以最少的夯击能，达到预期的加固效果。强夯法加固地基的思想起源于古老的夯实法，施工过程很简单。虽然强夯法目前应用很广泛，可是至今也没有一套完整的理论指导强夯法的设计。强夯法冲击地面时的荷载为非线性荷载，并且由于土体发生非线性塑性变形，运用传统的解析法去研究强夯的过程是非常困难的。目前的主要做法还是借助数值模拟技术进行求解。强夯法加固理论的研究主要集中于两个方面：动力固结理论和振动波密实理论。对于强夯法的施工参数与加固效果的关系研究，主要是一些工程人员结合自己的工程实际，开展了一些强夯实验研究。目前，对强夯法的设计主要是基于以往的实践经验。本文先总结了强夯法的发展历程及研究现状，分析了强夯法的动力固结理论和震动波密实理论，，在此基础上，对强夯各施工参数与加固效果的关系进行了深入的分析，以青岛市政建物流园地基强夯工程为例，分析了强夯施工参数组合与加固效果的关系。最后，使用当前非常流行的岩土工程数值模拟软件FLAC3D对该工程进行了数值模拟分析。本文所作的工作主要有：（1）从理论上对强夯加固机理进行了总结和分析，包括动力固结理论和震动波压密理论；（2）对强夯法的设计施工参数进行了全面分析，对各参数对加固效果的影响进行了详细的评价；（3）结合工程实例，分析了强夯法施工参数组合对地基加固效果的影响；（4）运用波动理论，推导出了夯锤夯击时，接触应力峰值大小，以及加载和卸载时间；（5）运用FLAC3D程序建立有限差分数值分析模型，将理论推导的接触应力时程输入到模型中，模拟强夯的施工过程；（6）对模型所作出的动力响应，进行了相关数据采集和计算机制图，对输出结果进行了全面系统的分析。分析了强夯后土体的应力应变情况、土体的加固深度以及单击夯沉量、单点夯沉量等，全方位研究了土体的应力和位移变化情况。
[Abstract]:Dynamic compaction is a convenient, economical and environmental protection method for foundation treatment. Ever since it came out, it has been very popular all over the world. For dynamic compaction, the ultimate goal is to achieve the desired reinforcement effect with minimum tamping energy. The idea of dynamic compaction is originated from the old ramming method, and the construction process is very simple. Although the dynamic compaction method is widely used at present, there is not a complete set of theory to guide the design of the dynamic compaction method. The dynamic compaction method is nonlinear when it hits the ground, and because of the nonlinear plastic deformation of soil, it is very difficult to use the traditional analytical method to study the process of dynamic compaction. At present, the main method is to use numerical simulation technology to solve the problem. The study of dynamic consolidation theory mainly focuses on two aspects: dynamic consolidation theory and vibration wave compaction theory. For the study of the relationship between the construction parameters of the dynamic compaction method and the reinforcement effect, some engineers have carried out some experimental research on dynamic compaction combined with their own engineering practice. At present, the design of dynamic compaction is mainly based on previous practical experience. In this paper, the development history and research status of dynamic compaction method are summarized, and the dynamic consolidation theory and vibration wave density theory of dynamic compaction method are analyzed. On this basis, the relationship between construction parameters of dynamic compaction and reinforcement effect is deeply analyzed. Taking the foundation dynamic compaction project of Qingdao Municipal Construction Logistics Park as an example, the relationship between the combination of dynamic compaction construction parameters and the reinforcement effect is analyzed. Finally, the geotechnical engineering numerical simulation software FLAC3D is used to simulate the geotechnical engineering. The main work done in this paper is as follows: 1) summarize and analyze the reinforcement mechanism of dynamic compaction theoretically, including dynamic consolidation theory and vibration wave compaction theory; 2) the design and construction parameters of dynamic compaction method are comprehensively analyzed, and the influence of each parameter on reinforcement effect is evaluated in detail. (3) combined with engineering example, the influence of dynamic compaction construction parameters combination on foundation reinforcement effect is analyzed. (4) the peak value of contact stress, loading and unloading time of tamping hammer are deduced by using wave theory. 5) the finite difference numerical analysis model is established by using FLAC3D program, and the time history of contact stress derived from theory is inputted into the model to simulate the construction process of dynamic compaction. 6) for the dynamic response of the model, the related data acquisition and computer mapping are carried out, and the output results are analyzed systematically. The stress and strain of the soil after dynamic compaction, the depth of soil reinforcement, the amount of single tamping and single point compaction are analyzed, and the variation of stress and displacement of soil is studied in all directions.
【学位授予单位】：石家庄经济学院
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU472.31

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