锦屏一级大理岩时效变形破裂规律及细观演化机理
发布时间：2018-09-10 18:57
【摘要】：岩石的时效力学特征及其破坏行为一直以来是土木水利工程及其相关领域中非常重要且异常复杂的研究课题之一。工程实践和相关研究表明，在许多情况下，岩石工程的破坏与失稳不是在开挖形成以后立即发生，岩体的应力和变形是随时间变化发展和不断地调整的，趋于稳定往往需要延续一个较长的时间，如时滞性岩爆、时效大变形等。岩体的这类变形破坏现象往往与脆性岩石在复杂应力条件下的时效变形破裂规律和细观演化机理有着密切关系，，但关于脆性岩石时效变形破裂细观演化机理的研究尚处于起步阶段，需要借助新的技术手段和理论方法进一步深化认识。鉴于此，本文在锦屏一级大理岩室内试验的基础上，借助三维颗粒流计算理论，引入BPM模型、PSC模型和超级单元clump技术，在构建基于矿物形颗粒状的大理岩细观力学模型的基础上，对不同应力水平和应力强度比以及不同分级条件下大理岩的时效力学特性进行研究，识别了脆性岩石时效变形破裂规律和细观演化机理。 本文的研究工作主要集中在如下几个方面： 1．给出了PSC模型的三维计算理论，该理论是以三维颗粒流细观平行粘结模型和线弹性断裂力学理论为基础，通过引入指数型细观内应力驱动的损伤速率，形成具有应力腐蚀颗粒破裂时间效应的细观平行粘结时效模型，用于描述岩石细观层面上的时效破裂。 2．对岩石瞬态和时效细观力学参数进行了敏感性分析，深入研究了这些细观力学参数对宏观力学响应及蠕变变形破坏的影响。结果表明：宏观弹性模量主要受颗粒弹性模量、平行粘结弹性模量、颗粒法切向刚度比、平行粘结法切向刚度影响，宏观峰值强度取决于平行粘结强度，1、2控制着蠕变断裂时间t f，岩石是否发生蠕变取决于a。 3．基于三维颗粒流理论，通过引入BPM模型、PSC模型和超级单元clump技术，并依据锦屏一级地下厂房大理岩的SEM矿物成份检测结果，建立了基于矿物形颗粒状的大理岩细观结构模型，在对细观力学参数敏感性分析的基础上，根据室内瞬态压缩试验和流变试验结果以及岩石细观力学参数识别方法，确定了大理岩的瞬态和时效细观力学参数，构建了大理岩的时效细观力学数值模型。 4．基于大理岩时效细观力学数值模型，对不同应力水平和应力强度比条件下大理岩进行了单级加载蠕变数值试验，研究了应力水平和应力强度比对大理岩时效变形破裂的影响规律及其细观演化机理。结果表明：应力水平控制着岩石的长期应力强度比；围压增加，岩石时效变形和破裂效应降低，失稳破坏时间延长或不失稳；应力强度比增加，岩石时效变形和破裂效应增加，破裂时间缩短。上述结果显示，随着围压或者应力强度比的增加，岩石细观时效演化机理本质上表现为张性裂纹扩展控制机制和剪切裂纹摩擦控制机制相互作用，此减彼增逐步过渡。 5．对大理岩进行了不同分级加载条件下蠕变数值试验，对比研究了分级数对岩石蠕变变形和时效破裂的影响规律。结果表明：分级数增加，岩石时效变形和破裂效应下降，时效破裂时间延长。
[Abstract]:The time-dependent mechanical characteristics and failure behavior of rock have always been one of the most important and complex research topics in civil engineering and related fields. Engineering practice and related research show that in many cases, the failure and instability of rock engineering do not occur immediately after excavation, but the stress and deformation of rock mass are The deformation and failure phenomena of rock mass are often closely related to the law of time-dependent deformation and fracture and the mechanism of micro-evolution of brittle rock under complex stress conditions, but about brittle rock. In view of the fact that the study on the meso-evolution mechanism of aging deformation and fracture is still in its infancy and needs to be further deepened by means of new technical means and theoretical methods, this paper introduces BPM model, PSC model and super-unit clump technology to construct the foundation on the basis of the laboratory test of Jinping first-grade marble and the theory of three-dimensional particle flow calculation. Based on the microscopic mechanical model of mineral-like granular marble, the aging mechanical properties of marble under different stress levels, stress-strength ratios and grading conditions are studied. The aging deformation and fracture laws and microscopic evolution mechanism of brittle rock are identified.
The research work in this paper is mainly concentrated on the following aspects:
1. A three-dimensional computational theory of PSC model is presented. Based on the three-dimensional particle flow parallel bond model and the linear elastic fracture mechanics theory, a meso-parallel bond aging model with stress corrosion particle rupture time effect is developed by introducing an exponential damage rate driven by internal stress. The breakdown of age at the level of perception.
2. Sensitivity analysis of rock transient and time-dependent meso-mechanical parameters is carried out, and the effects of these parameters on macro-mechanical response and creep deformation and failure are studied in depth. The results show that the macro-elastic modulus is mainly affected by the elastic modulus of particles, the elastic modulus of parallel bonding, the tangential stiffness ratio of particles, and the tangential rigidity of parallel bonding. The macroscopic peak strength depends on the parallel bond strength, 1,2 controls the creep fracture time t f, and whether the rock creeps depends on a.
3. Based on the theory of three-dimensional particle flow, by introducing BPM model, PSC model and super-unit clump technology, and according to the results of SEM mineral composition test of marble in Jinping I underground powerhouse, a micro-structure model of marble with mineral shape and granular shape is established. Based on the sensitivity analysis of micro-mechanical parameters, and according to the indoor transient state, the micro-structure model of marble is established. The results of compression test and rheological test as well as the identification method of rock micro-mechanical parameters are used to determine the transient and time-dependent micro-mechanical parameters of marble, and the time-dependent micro-mechanical numerical model of marble is constructed.
4. Based on the numerical model of marble aging micro-mechanics, the creep numerical tests of marble under different stress levels and stress-strength ratios were carried out under single-stage loading. The effects of stress levels and stress-strength ratios on the aging deformation and fracture of marble and its micro-evolution mechanism were studied. The results show that with the increase of confining pressure or stress-strength ratio, the evolution mechanism of rock aging is essentially the same. It is shown that the tensile crack growth control mechanism interacts with the shear crack friction control mechanism, and the change is gradual.
5. The creep numerical tests of marble under different staged loading conditions are carried out, and the effects of stages on creep deformation and time-dependent fracture of rock are studied comparatively.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU45
本文编号：2235324
[Abstract]:The time-dependent mechanical characteristics and failure behavior of rock have always been one of the most important and complex research topics in civil engineering and related fields. Engineering practice and related research show that in many cases, the failure and instability of rock engineering do not occur immediately after excavation, but the stress and deformation of rock mass are The deformation and failure phenomena of rock mass are often closely related to the law of time-dependent deformation and fracture and the mechanism of micro-evolution of brittle rock under complex stress conditions, but about brittle rock. In view of the fact that the study on the meso-evolution mechanism of aging deformation and fracture is still in its infancy and needs to be further deepened by means of new technical means and theoretical methods, this paper introduces BPM model, PSC model and super-unit clump technology to construct the foundation on the basis of the laboratory test of Jinping first-grade marble and the theory of three-dimensional particle flow calculation. Based on the microscopic mechanical model of mineral-like granular marble, the aging mechanical properties of marble under different stress levels, stress-strength ratios and grading conditions are studied. The aging deformation and fracture laws and microscopic evolution mechanism of brittle rock are identified.
The research work in this paper is mainly concentrated on the following aspects:
1. A three-dimensional computational theory of PSC model is presented. Based on the three-dimensional particle flow parallel bond model and the linear elastic fracture mechanics theory, a meso-parallel bond aging model with stress corrosion particle rupture time effect is developed by introducing an exponential damage rate driven by internal stress. The breakdown of age at the level of perception.
2. Sensitivity analysis of rock transient and time-dependent meso-mechanical parameters is carried out, and the effects of these parameters on macro-mechanical response and creep deformation and failure are studied in depth. The results show that the macro-elastic modulus is mainly affected by the elastic modulus of particles, the elastic modulus of parallel bonding, the tangential stiffness ratio of particles, and the tangential rigidity of parallel bonding. The macroscopic peak strength depends on the parallel bond strength, 1,2 controls the creep fracture time t f, and whether the rock creeps depends on a.
3. Based on the theory of three-dimensional particle flow, by introducing BPM model, PSC model and super-unit clump technology, and according to the results of SEM mineral composition test of marble in Jinping I underground powerhouse, a micro-structure model of marble with mineral shape and granular shape is established. Based on the sensitivity analysis of micro-mechanical parameters, and according to the indoor transient state, the micro-structure model of marble is established. The results of compression test and rheological test as well as the identification method of rock micro-mechanical parameters are used to determine the transient and time-dependent micro-mechanical parameters of marble, and the time-dependent micro-mechanical numerical model of marble is constructed.
4. Based on the numerical model of marble aging micro-mechanics, the creep numerical tests of marble under different stress levels and stress-strength ratios were carried out under single-stage loading. The effects of stress levels and stress-strength ratios on the aging deformation and fracture of marble and its micro-evolution mechanism were studied. The results show that with the increase of confining pressure or stress-strength ratio, the evolution mechanism of rock aging is essentially the same. It is shown that the tensile crack growth control mechanism interacts with the shear crack friction control mechanism, and the change is gradual.
5. The creep numerical tests of marble under different staged loading conditions are carried out, and the effects of stages on creep deformation and time-dependent fracture of rock are studied comparatively.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU45
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