静力触探贯入行为分析与实践

发布时间：2018-05-18 21:45

本文选题：静力触探 + 贯入机理　；参考：《长沙理工大学》2013年硕士论文

【摘要】：静力触探（Cone Penetration Test，CPT）技术与传统的测试技术相比，其具有可测得连续的土体资料、测试数据精确且性能稳定、测试快速可连续贯入、可测得土体深层数据等优点。静力触探作为一种可靠的兼具勘探和测试双重作用的岩土工程测试技术，已被广大岩土工程技术人员应用于岩土工程中，但目前对静力触探的贯入机理还无法在理论上完全解释清楚，因此对其许多方面的研究工作还处在长期不懈的探索之中，相关学科至今仍然不能完全从理论层面上分析贯入器与土体之间的应力场和位移场的相关问题。因此，对贯入器的贯入行为进行更深入的分析研究，对静力触探技术的发展和推广具有重要的理论意义和工程应用价值。本论文首先查阅了大量国内外文献资料，分析了国内外承载力理论、孔穴扩张理论、有限元分析法等的研究现状及其在实际工程中的应用情况。通过静力触探有关测试结果分析匀质砂土、匀质粉质土以及粘土-砂土双层模型中触探贯入参数的变化规律，并探讨静力触探贯入机理。然后采用应力跌落的简化应力应变模型，考虑土体屈服后所表现出的强度软化特性，根据空间准滑动面（SMP）理论和平面应变轴对称问题的柱形孔穴扩张基本方程，在塑性区内采用不相关联流动法则和对数应变定义分别考虑剪胀效应和大应变特性，推导出一般粘性土中基于圆柱孔穴扩张理论的弹性区域理论解和塑性区域小应变理论相关解。最后考虑静力触探过程中土体的大变形特性以及土体的剪胀性质，采用莫尔-库仑模型，分析建立了有限元分析计算模型，应用有限元分析软件ABAQUS进行数值模拟，计算分析静力触探探头贯入后土体的位移、应力的变化规律，通过工程实例的计算分析验证建立的有限元分析模型的可行性。同时，比较了不同土体参数对应力与位移场的影响规律，建立土体各物理参数与有限元计算的锥尖阻力和侧壁阻力之间的计算公式，并与经验公式进行比较分析。
[Abstract]:Compared with the traditional testing technique, the static Penetration Penetration testing (CPT) technique has the advantages of measuring continuous soil mass data, accurate and stable testing data, rapid and continuous penetration, and so on. As a reliable geotechnical engineering testing technology with both exploration and test functions, static penetration exploration has been applied to geotechnical engineering by the vast number of geotechnical personnel. But at present, the penetration mechanism of static penetration can not be fully explained in theory, so many aspects of its research work is still in the process of long-term unremitting exploration. Up to now, the related problems of stress field and displacement field between the penetrator and the soil can not be completely analyzed from the theoretical level. Therefore, it is of great theoretical significance and engineering application value for the development and popularization of static penetration technology to conduct more in-depth analysis and research on the penetration behavior of the penetrator. In this paper, a large number of literature at home and abroad are reviewed, and the research status and application of the theory of bearing capacity, the theory of cavity expansion, the finite element analysis and so on in practical engineering are analyzed in this paper. The variation of penetration parameters in homogeneous sandy soil, homogeneous silty soil and clay sand bilayer model is analyzed by the results of static penetration test, and the penetration mechanism of static penetration is discussed. Then, the simplified stress-strain model of stress drop is adopted, considering the strength softening characteristic of soil after yielding, according to the theory of spatial quasi-sliding surface (SMP) and the basic equation of cylindrical cavity expansion for plane strain axisymmetric problem. In the plastic region, the shear expansion effect and the large strain characteristic are considered by the law of disassociation flow and the definition of logarithmic strain, respectively. The theoretical solution of elastic region and the correlation solution of small strain theory of plastic region based on cylindrical cavity expansion theory in general cohesive soil are derived. Finally, considering the characteristics of large deformation and shear dilatancy of soil in the process of static penetration, a finite element analysis model is established by using Mohr Coulomb model, and the finite element analysis software ABAQUS is used to carry out numerical simulation. The variation law of soil displacement and stress after the penetration of the static penetration probe is calculated and analyzed. The feasibility of the established finite element analysis model is verified by the calculation and analysis of an engineering example. At the same time, the effects of different soil parameters on the force and displacement field are compared, and the formulas between the physical parameters of soil and the cone tip resistance and lateral wall resistance calculated by finite element method are established and compared with the empirical formula.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU43

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