【作者】 张志强；

【导师】 李宁；

【作者基本信息】 西安理工大学 ， 岩土工程， 2009， 博士

【摘要】 针对岩体工程中最常见、最重要的非贯通裂隙岩体,以典型物理模型试验为基础,通过建立能反映不连续性、非均匀性、各向异性、非弹性等裂隙岩体基本特性的细观数值分析模型,开展了系统的非贯通裂隙岩样破坏模态与细观破坏机理数值试验研究；根据经物理模型试验标定的细观数值试验分析成果,总结了裂隙几何分布特征、裂隙面摩擦性以及应力条件对非贯通裂隙岩体破坏模式与强度的影响规律,建立了能反映裂隙几何分布特征、裂隙力学性质、岩块力学性质以及侧压等因素的非贯通裂隙岩体宏观变形参数、强度参数计算分析模型,并对所建立的宏观力学参数计算分析模型进行了讨论与验证。主要创新点如下：(1)为反映裂隙岩体的不连续性、非均匀性、各向异性、非弹性,建立了非均匀损伤破坏模型；通过典型的室内物理模型试验,验证了该非均匀损伤破坏模型的合理性与正确性；利用分析系统中特有的解析刚体模型改进了裂隙岩体细观破坏数值试验边界条件与加载板的模拟方法。(2)利用所建的非均匀损伤破坏数值模型,对含一条、两条、多条(9条)裂隙的非贯通裂隙岩样,分别进行了系统的破坏模式与细观机理数值试验,着重分析了试样的第一主应力场、剪应力场、次生裂纹起裂与发展路径以及峰值强度等,总结了裂隙几何分布特征、裂隙面摩擦性质以及侧压对试样应力场、次生裂纹起裂与发展路径以及试样峰值强度的影响规律,提炼了非贯通裂隙岩体典型的破坏模式——单平面模式和台阶模式。(3)基于变形等效原理和裂隙岩体细观变形特征,推导了含单组非贯通裂隙岩体变形参数(变形模量、泊松比、剪切模量)计算分析模型,研究了岩体变形模量、泊松比、剪切模量等变形参数随岩体裂隙连通率、裂隙倾角、裂隙厚度率的变化规律；进一步推导了含多组非贯通裂隙岩体变形模量、泊松比计算分析模型,研究了含多组裂隙岩体的变形模量、泊松比随裂隙几何分布特性、裂隙变形参数、岩块变形参数的变化规律；并利用物理模型试验结果对计算分析模型进行了验证。(4)基于单平面破坏和台阶破坏两种模式假定,分别推导了发生单平面破坏、台阶破坏条件下非贯通裂隙岩体宏观剪切强度参数(粘聚力、内摩擦角)、抗压强度计算公式,并提出了相应的强度准则；进一步讨论了非贯通裂隙岩体剪切强度以及其参数、抗压强度受裂隙粘聚力、裂隙摩擦角、裂隙连通率、裂隙间距、裂隙排距、裂隙倾角、岩桥粘聚力、岩桥摩擦角、岩桥倾角的影响关系；对建立的分析计算公式进行了验证与讨论。更多还原

【Abstract】 Fractured rock mass is one of the most common and important engineering materials in many industries such as energy, transportation, hydroelectric engineering, and mining. This study is focused on the meso-mechanical characteristics of fractured rock mass with nonpenetrative fissures during failure, and estimation the deformation and strength mechanical parameters by the scientific methods. To simulate the failure of fractured rock mass with nonpenetrative fissures, a meso-mechanical analysis model has been set up in this paper. A series of numerical model tests have been carried out to study the characteristics of deformation, distribution of stress, characteristics of failure, and process of failure, that related to the fractured rock mass. From the conclusions draw from the results after the numerical model tests, some laws that reflect the change of increasing and decreasing of strength for the fractured rock mass and some typical failure models of fractured rock mass have been presented. A new method of estimating the deformation and strength parameters, such as deformation modulus, poisson’s ratio, shear modulus, inner cohesion, inner friction angle, have been derived by theoretic method and taking the fissure’s factors and conditions of applied stress. Main summarizations listed as blow:(1) To simulate the failure of the fractured rock mass with nonpenetrative fissures, an inhomogeneous damage plasticity model is assembled in ABAQUS, by adding the Weibull distribution for mechanical parameters of rock. The numerical model is validated by the results from some typical physical model tests carried out on MTS system. The numerical model can represent the features possessed by fractured rock mass, such as discontinuous, inhomogeneous, anisotropic, and not elastic. In the numerical model, an analytical rigid body model is applied to simulate the loading board in physical model test, which shows a well simulation of boundary condition in numerical tests.(2)A series of numerical model tests are performed by the inhomogeneous damage plasticity model on ABAQUS, these tests include model rock mass sample with one crack, two cracks, or 9 cracks. The key factors influenced the strength and deformation of rock mass, such as dip of fissure, confining pressure, friction angle of fissure, layout of fissure, are studied in these numerical model tests. Some mechanical phenomena on model samples are discussed, for example 1 st principle stress, shear stress, initiation of induced crack, trace of failure and peak compressive strength. According to these results, some laws that reflect the change of increasing and decreasing of strength for fractured rock mass with the change of dip of fissure, confining pressure, friction angle of fissure, layout of fissure, and some typical failure models of fractured rock mass are presented(3)Based on the theory of equilibrium of deformation, a formula is derived by theoretic method, taking the layout of fissure and directions of applied force. The formula can be utilized to calculate the deformation modulus, poisson’s ratio, and shear modulus, taking the deformation modulus, poisson’s ratio of intact rock, filling, tangential stiffness, and normal stiffness. The validity of the formula is verified by the reasonable analysis. According to the formula, some change laws of deformation modulus, poisson’s ratio, shear modulus, with the change of dip of fissure and layout of crack, are presented.(4)Based on the hypothesis of simultaneous failure on the failure zone and two failure models, Formulas are derived by theoretic method, taking the layout of fissures, fissure persistence, to calculate the inner cohesion, inner friction angle, and compressive strength. The validity of the formula is verified by the theoretic analysis. According to these formulas, some laws that reflect the change of inner cohesion, inner friction angle, and compressive strength, with the change of dip of fissure and layout of fissure, are presented.更多还原