脆性岩石热—力—损伤耦合机理及数值模拟研究

发布时间：2018-06-15 14:01

本文选题：脆性岩石 + 热—力—损伤耦合　；参考：《武汉大学》2013年博士论文

【摘要】：高放核废料深地质处置是一个关系到国计民生的综合性问题,具有多学科交叉的特点。它对岩石力学工程领域提出了许多挑战性的科学和技术课题,如复杂岩体及其赋存环境的热-水-力耦合问题等。其中,脆性岩石的热-力-损伤耦合问题作为复杂岩体多场耦合问题的一个重要方面也得到国内外学者的重点关注。本文以国际合作研究计划DECOVALEX-2011的B子课题“硬岩热-力耦合作用研究”、国家优秀青年科学基金项目“岩土体多场耦合效应与渗流控制(No.51222903)”、国家自然科学基金面上项目“考虑多场耦合效应的核废料深地质处置库围岩传输特性演化机制(No.51179136)"和国防科工委高放核废料地质处置研究项目“基于THMC耦合的高放废物地质处置安全性评价”为背景,以脆性岩石为研究对象,以脆性岩石热-力耦合作用诱发的损伤过程及热传导特性演化规律为出发点,采用理论分析和试验验证相结合的方法,重点研究了温度和应力耦合作用下脆性岩石的损伤演化特性和热传导特性演化规律,分析了岩石在耦合作用下的热能传输规律和渐进破坏过程。论文的主要研究工作和成果概括如下： (1)研究了脆性岩石在开挖、热应力耦合条件下的宏细观损伤机制。介绍了细观力学均匀化方法,研究了含微裂纹脆性岩石宏观有效弹性张量；将含微裂纹脆性岩石看作一个热力学系统,分析了描述岩石细观损伤演化过程的基本内变量,研究了非等温条件下考虑热-力耦合作用的细观损伤力学模型；采用瑞典Aspo闪长岩的三轴压缩试验数据对细观损伤力学模型有效性与合理性进行了验证。 (2)研究了多场耦合条件下脆性岩石有效热传导特性的演化机制。分析了岩石有效热传导系数的影响因素,包括岩石的矿物组成、孔隙率、饱和流体及饱和度、温度和应力等；介绍了岩石有效热传导特性的、Viener界限和Hashin-Shtrikman界限；将岩石表征单元体看作无限大基质和非均匀椭球夹杂的混合物,从热传导问题基本方程出发,运用细观均匀化方法导出了有效热传导系数的一般表达式,并根据椭球夹杂问题基本解得到了基于不同均匀化方法的有效热传导特性张量；分析了有效热传导特性张量的Voigt界限和Reuss界限,讨论了有效热传导张量的各向异性特征,分析了岩石有效热传导特性与结构变化及损伤演化之间的内在联系；运用该模型研究了瑞典Aspo闪长岩在加载过程中的有效热传导特性的演化规律；基于膨润土细观结构特征,采用细观均匀化方法研究了我国高庙子膨润土的有效热传导特性。 (3)研究了脆性岩石热-力-损伤耦合数值分析方法。从不可逆热力学的角度,考虑岩石在温度和应力作用下的损伤与有效热传导特性演化,基于等效连续介质分析模型,建立了脆性岩石的热-力-损伤耦合控制方程,采用Galerkin方法和有限差分法对控制方程组进行离散,建立了有限元计算格式,研发了三维应力场与温度场耦合分析程序。 (4)结合国际合作项目DECOVALEX-2011计划B子课题,开展了脆性岩石热-力-损伤耦合数值模拟研究。介绍了在瑞典Aspo硬岩地下试验室开展的APSE(Aspo Pillar Stability Experiment)岩柱稳定性试验：研究了在开挖应力扰动和温度扰动共同作用下试验区域温度场、应力场和变形场的分布规律,揭示了试验岩柱在热-力耦合作用下的渐进破坏规律。
[Abstract]:The deep geological disposal of high radioactive waste is a comprehensive problem related to the national economy and the people's livelihood. It has the characteristics of multidisciplinary and interdisciplinary. It has put forward many challenging scientific and technical topics in the field of rock mechanics engineering, such as the hot water force coupling problem of complex rock mass and its occurrence environment. As an important aspect of the multi field coupling problem of complex rock mass, it has also been paid more attention by scholars both at home and abroad. This paper, based on the B sub project of the international cooperative research program DECOVALEX-2011, "Research on the thermal force coupling of hard rock", the National Excellent Youth Science foundation project "multi field coupling effect and seepage control (No.51222903)", The project "the evolution mechanism of the surrounding rock transmission characteristics of nuclear waste deep geological disposal repositories considering multi field coupling effect (No.51179136)" and the project of high radioactive waste geological disposal research project of the national defense science and Technology Commission "based on THMC coupled high level waste geological disposal safety assessment" as the background, the research object of fragile rock as the research object. The damage process and the evolution of heat conduction characteristics are the starting point of the coupled thermal force coupling of brittle rocks. By combining theoretical analysis with experimental verification, the damage evolution and heat conduction characteristics of brittle rocks under the coupling of temperature and stress are studied, and the thermal energy of the rock under coupling is analyzed. The main research work and achievements are summarized as follows:
(1) the macro mesoscopic damage mechanism of brittle rock under the condition of excavation and thermal stress coupling is studied. The meso mechanical homogenization method is introduced, and the macroscopic effective elastic tensor of brittle rock with micro cracks is studied, and the brittle rock with micro cracks is considered as a thermodynamic system, and the basic internal variables describing the evolution process of the rock meso damage are analyzed. The mesoscopic damage mechanics model for thermal force coupling under non isothermal conditions is studied, and the validity and rationality of the meso damage mechanics model are verified by the three axial compression test data of the Swedish Aspo diorite.
(2) the evolution mechanism of effective heat conduction characteristics of brittle rocks under multi field coupling is studied. The factors affecting the effective thermal conductivity of rock are analyzed, including mineral composition, porosity, saturated fluid and saturation, temperature and stress, etc., and the effective heat conduction characteristics of rock, Viener boundary and Hashin-Shtrikman limit are introduced. The rock characterization unit is regarded as an infinite matrix and an inhomogeneous ellipsoid mixture. From the basic equation of the heat conduction problem, the general expression of the effective heat conduction coefficient is derived by the meso homogenization method, and the effective heat conduction tensor based on the inhomogeneous homogenization method is obtained according to the basic solution of the ellipsoid inclusion problem. The Voigt boundary and Reuss boundary of the effective heat conduction tensor are analyzed, the anisotropic characteristics of the effective heat conduction tensor are discussed, and the internal relations between the effective heat conduction characteristics of the rock and the structural changes and the damage evolution are analyzed. The effective heat conduction characteristics of the Swedish Aspo diorite during loading are studied by using the model. Based on the meso structural characteristics of bentonite, the effective heat transfer characteristics of high Miao Zi bentonite in China were studied by meso scale homogenization method.
(3) the numerical analysis method for the thermal force damage coupling of brittle rocks is studied. In the angle of irreversible thermodynamics, the damage and effective heat conduction characteristics of rock under the action of temperature and stress are considered. Based on the equivalent continuous medium analysis model, the coupling control equation of the thermal force damage of brittle rock is established, and the Galerkin method and the finite difference are adopted. Discrete method is used to discretize the governing equations, and the finite element calculation format is established, and the three-dimensional stress field and temperature field coupling analysis program is developed.
(4) combining the B sub project of the DECOVALEX-2011 project of the international cooperation project, the numerical simulation of the thermal force damage coupling of brittle rocks is carried out. The stability test of the APSE (Aspo Pillar Stability Experiment) rock column in the Aspo hard rock underground test room in Sweden is introduced. The experiment is carried out under the joint action of the stress disturbance and the temperature disturbance in the excavation. The distribution law of regional temperature field, stress field and deformation field reveals the progressive failure law of test rock column under thermo mechanical coupling.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU45

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