基于Mohr-Coulomb模型土体内柱形孔扩张的弹塑性解及应用

发布时间：2018-05-14 08:37

本文选题：塑性极限平衡分析 + 柱形孔扩张　；参考：《北京交通大学》2014年硕士论文

【摘要】：土的抗剪强度参数对于岩土工程的设计和施工非常重要,但是现有原位测试中还没有能够直接获得土体抗剪强度参数的原位测试方法。为了解决这个问题,本文基于Mohr-Coulomb模型和Vesic圆孔扩张理论对土体内的柱形孔扩张问题进行了弹塑性分析,并根据得到的解析解提出了一种新型的原位测试仪的概念设计。本论文的主要工作及成果如下： 1)进行了大量相关文献的调研和阅读,对国内外的研究成果进行了归纳和整理；分析了当前理论研究现状,深入了解圆孔扩张理论的原理、应用情况以及各种理论的优缺点。 2)基于弹塑性理论,利用极限平衡分析方法,在现有的弹性分析的基础上对均匀围压下和双向不等围压下的柱形孔扩张问题进行了塑性分析；推导出了弹性极限压力与土体抗剪强度参数的关系,孔体积的变化与内压力p及抗剪强度参数的关系,孔内压力与塑性区分布范围的关系,塑性区的应变和位移分量,孔周土体塑性区的变形速率,以及小应变条件下孔壁的塑性变形。 3)采用有限元软件MIDAS对均匀围压下和双向不等围压下的柱形孔扩张问题进行数值了仿真分析,分析了均匀围压下柱形孔周塑性区半径的开展与孔内压力的关系,不同抗剪强度参数下塑性区范围的变化规律,以及双向不等围压下的弹性极限应力,并与理论分析和推导的结果进行对比和分析,验证了推导得到的理论解。 4)分析了当前国内外根据原位测试方法求取岩土体参数的不足,以前文推导出的弹性极限压力和孔的体积变化与土体抗剪强度参数的关系为原理,提出了一种新型的直接测量土体抗剪强度参数的原位测试装置概念设计。
[Abstract]:The shear strength parameters of soil are very important for the design and construction of geotechnical engineering, but there is no in-situ testing method to obtain the shear strength parameters directly in situ testing. In order to solve this problem, based on the Mohr-Coulomb model and Vesic circular hole expansion theory, the elastoplastic analysis of cylindrical pore expansion in soil is carried out, and the conceptual design of a new type of in-situ testing instrument is proposed based on the analytical solution obtained. The main work and results of this thesis are as follows: 1) A large number of related literatures are investigated and read, and the research results at home and abroad are summarized and sorted out, and the current theoretical research situation is analyzed, and the principle, application and advantages and disadvantages of the theory of circular hole expansion are deeply understood. 2) based on the elastic-plastic theory and using the limit equilibrium analysis method, the plastic analysis of cylindrical hole expansion under uniform confining pressure and bidirectional unequal confining pressure is carried out on the basis of the existing elastic analysis. The relationship between the elastic limit pressure and the shear strength parameter, the relationship between the pore volume and the internal pressure p and the shear strength parameter, the relation between the pressure in the hole and the distribution range of the plastic zone, the strain and the displacement component in the plastic zone are deduced. The deformation rate of the plastic zone around the hole and the plastic deformation of the hole wall under the condition of small strain. 3) the expansion of cylindrical holes under uniform confining pressure and bidirectional unequal confining pressure is numerically simulated by finite element software MIDAS, and the relationship between the development of plastic zone radius of cylindrical holes under uniform confining pressure and the pressure inside the hole is analyzed. The variation of the range of plastic zone under different shear strength parameters and the elastic limit stress under bidirectional unequal confining pressure are compared and analyzed with the theoretical analysis and derivation, and the theoretical solution is verified. 4) this paper analyzes the shortage of calculating the parameters of rock and soil according to the in-situ testing method at home and abroad. The principle of the relationship between the elastic limit pressure and the volume change of the pore and the shear strength parameter of the soil is deduced in the previous paper. A new type of in-situ testing device for directly measuring shear strength parameters of soil is presented in this paper.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU413

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