层状岩体力学参数的状态相关性研究

发布时间：2018-03-25 18:40

本文选题：层状岩体　切入点：力学参数　出处：《长沙理工大学》2013年硕士论文

【摘要】：如何合理确定岩体力学参数一直是岩体力学领域及工程建设中的重要研究课题。岩体力学参数的取值不仅与完整岩块的材料性质有关，还与工程岩体所处的状态紧密相联。本文在岩体力学参数数值试验模型辨识的基础上，通过大量岩体数值试验，研究了岩体结构特征、应力状态、孔隙水压力等因素对层状岩体变形模量、抗剪断强度参数的影响。论文的主要研究工作及成果如下： 1）回顾了岩体力学参数的确定方法及状态相关性研究的国内外现状，总结和分析了影响岩体力学参数的状态因素和研究方法，提出了采用数值仿真手段研究岩体结构形态特征、应力状态、孔隙水压力等因素对层状岩体力学参数取值的影响。在此基础上，以淋溪河水电站坝址区部分岩体刚性承压板试验和现场直剪试验结果为依据，运用计算机模拟技术对其进行数值仿真试验，通过物理试验和数值试验结果的对比分析，说明了以上两种岩体力学试验的模拟方法是可行的。 2）基于大量刚性承压板数值试验和现场直剪数值试验，研究了岩体结构特征对层状岩体力学参数的影响规律。通过对承压板数值试验中各类岩体铅直位移等值线的分布及试验结果进行分析发现，层状岩体变形特征具有明显的结构效应，结构面倾角、间距、刚度对岩体变形模量的影响是相互影响的。同时，为进一步探究结构特征对层状岩体变形模量的影响，采用解析法对同类层状岩体的变形模量进行了研究，得到的成果与数值试验法基本相同。通过模拟结构面产状不同的层状岩体现场直剪试验，采用莫尔-库伦准则对试验数据进行整理，探究了层状岩体抗剪断强度参数的结构面产状效应。 3）通过模拟不同初始应力大小下的层状岩体现场承压板试验，探讨了初始应力对层状岩体变形模量的影响。在侧压力系数为0.5的应力环境下，层状岩体变形模量会随着初始应力的增加而变大，但当初始应力增至某一特定值时，层状岩体变形模量的变化特征会因结构面倾角的不同而出现较大差异。通过模拟初始应力水平不同的层状岩体现场直剪数值试验，研究了初始应力大小对层状岩体抗剪断强度参数的影响。在侧压力系数为0.5的应力环境下，随着初始应力的增大，除倾角0°的层状岩体抗剪断强度参数保持不变外，其他倾角层状岩体粘聚力呈线性增加但内摩擦角基本保持不变。基于同类层状岩体的现场直剪、室内直剪、三轴压缩等数值试验结果，阐明了岩体加载状态对层状岩体抗剪断强度参数的影响。由于同类岩体在不同试验方法中的加载状态及变形破坏机制均不同，其所得抗剪断强度参数值存在较大差异。 4）通过模拟含不同孔隙水压力的层状岩体现场承压板试验和现场直剪试验，探究了孔隙水压力对层状岩体力学参数的影响规律。研究成果表明：层状岩体变形模量随孔隙水压力的增加而变大，，但变化特征因结构面倾角不同而不同；随着孔隙水压力的增加，层状岩体的粘聚力呈线性减小，内摩擦角基本不变。 5）基于不同状态下层状岩体数值试验研究成果，建立了应用参考状态岩体力学参数和状态影响因子求解不同状态下的层状岩体力学参数的函数关系表达式。
[Abstract]:How to determine the mechanical parameters of rock mass has been an important research topic in the field of rock mechanics and engineering construction. The values of mechanical parameters of rock mass is not only related to the material properties of intact rock, which is closely related to the state of rock mass and engineering. In this paper, the mechanical parameters of rock mass numerical test model identification, through a large number of numerical tests of rock mass and study the characteristics of rock mass structures, stress, pore water pressure and other factors on the influence of deformation modulus, shear strength parameters. The main research work and achievements of the thesis are as follows:
1) correlation method and research status at home and abroad were reviewed to determine the mechanical parameters of rock mass, summarizes and analyzes the status of affect factors and research methods of rock mechanics parameters, puts forward the research of rock mass structure characteristics by means of numerical simulation, the stress state, the effect of pore water pressure and other factors on the mechanical parameters of layered rock mass. On this basis, the rigid bearing plate rock part of Linxi River Hydropower Station dam site test and in-situ direct shear test results as the basis, using computer simulation technology to carry out the numerical simulation test, through comparative analysis of physical experiment and numerical experiment results, the simulation method of the above two kinds of rock mechanics test is feasible.
2) a large number of numerical direct shear tests of rigid bearing plate numerical test and field based on the influence of rock mass structure on the mechanical parameters of layered rock mass. According to the analysis of the distribution and the test results of the numerical experiments of rock bearing plate vertical displacement contour, the deformation characteristics of layered rock mass structure has obvious effect, surface structure angle, distance, influence of stiffness on the deformation modulus of rock is the mutual influence. At the same time, to further explore the influence of structure deformation modulus of layered rock mass, the analytical method of similar layered rock mass deformation modulus was studied, and results of numerical experiments were basically the same. Through field simulation of layered rock structure surface the shape of different direct shear test, using Mohr criterion of Kulun test data, structural plane effect on shear strength parameters of layered rock mass Should be.
3) through the simulation of different initial stress field of layered rock mass stress under bearing plate test, discusses the influence of initial stress on deformation modulus. The lateral pressure coefficient is 0.5 under environmental stress, modulus will increase with initial stress and large deformation of layered rock mass, but when the initial stress increased a specific value, variation of deformation modulus of layered rock mass due to obliquity is different and larger difference. By simulating the initial stress field of layered rock mass numerical direct shear tests on different force levels, studied the effects of initial stress on rock shear strength parameters. The lateral pressure coefficient should be 0.5, with the increase of the initial stress, in addition to the layered rock mass at an angle of 0 degrees shear strength parameters remain unchanged, the other angle of layered rock cohesion increases linearly but the internal friction angle based on the remained basically unchanged. The kind of layered rock mass shear, direct shear, three axial compression etc. The results of numerical experiments, illustrates the influence of loading condition of rock shear strength parameters of layered rock mass. The loading state of similar rock mass in different test methods and the deformation and failure mechanism are different, there is a great difference between the shear strength parameters.
4) direct shear test of layered rock mass of the bearing plate test and field simulation with different pore water pressure, explores the influence of pore water pressure on the mechanical parameters of layered rock mass. The results show that the deformation modulus of layered rock mass with the increase of pore water pressure and change, but change characteristics because the obliquity varies; with the increase of pore water pressure, layered rock cohesion linearly decreases, the internal friction angle is basically the same.
5) based on the numerical experimental research results of stratified rock mass under different conditions, a functional relation formula for solving the mechanical parameters of layered rock mass under different conditions is established by referring to the state parameters of rock mass and the state influence factor.

【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】：TU45

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