化学-温度-应力耦合作用对岩石力学性能的影响

发布时间：2018-06-15 11:55

本文选题：岩石 + 温度　；参考：《上海理工大学》2014年硕士论文

【摘要】：岩石所赋存的地质条件十分复杂,在众多影响岩石破坏的因素中,化学、温度、应力的影响十分显著。本文对经历化学-温度-应力耦合作用的花岗岩进行了一系列相关的力学试验研究,分析了多因素下岩石的力学性能的变化规律和损伤机理。从单一因素出发,逐步研究多因素对岩石力学性能的影响,因此,本文主要从以下四个方面开展研究:(1)通过研究20℃~800℃高温状态的花岗岩在自然冷却(在炉膛中)和水中快速冷却后的力学性能,分析了花岗岩在单轴压缩下的破坏模式,从纵波波速、应力-应变曲线、峰值应力、轴向峰值应变、径向峰值应变、杨氏模量和微观结构等方面探讨了温度和冷却方式对花岗岩力学性能的影响。试验结果表明,花岗岩的纵波波速、峰值应力和杨氏模量随经历温度的升高而衰减,水中快速冷却比自然冷却衰减的幅度更大。这说明温度越高,花岗岩的力学性能劣化越严重,水中快速冷却产生的热冲击加剧了花岗岩力学性能的劣化。花岗岩水中快速冷却后的峰值应变小于自然冷却后的峰值应变,说明高温状态的花岗岩水中快速冷却后,其脆性比自然冷却后更加显著。(2)通过研究花岗岩在不同化学溶液(水、Na OH溶液和HNO3溶液)中浸泡并冻融循环后的力学性能,分析了花岗岩在不同化学溶液中溶蚀及经历不同冻融循环次数后,在单轴压缩作用下基本力学性能的变化规律。试验结果表明,在水、Na OH和HNO3溶液中,随着冻融循环次数的增加,花岗岩的纵波波速、杨氏模量、相对杨氏模量和峰值应力均呈指数函数减小,纵波波速损失率和峰值应力损失率均呈幂函数增加;轴向峰值应变按Guass函数变化。HNO3对花岗岩的断口形貌影响比较严重,而Na OH影响较弱。随着冻融循环次数的增加,HNO3溶液作用过的花岗岩初期损伤劣化较大,后期损伤劣化较小,而Na OH溶液作用过的花岗岩初期损伤劣化较小,后期损伤劣化较大。(3)通过研究化学-温度-应力耦合作用(即在水、Na OH溶液和HNO3溶液浸泡和冻融循环、高温作用并进行单轴压缩)后花岗岩的力学性能,分析了花岗岩经化学-温度-应力耦合作用后基本力学性能的变化规律。试验结果表明,化学-温度-应力耦合作用下,温度对破坏模式产生了一定的影响,主要表现在改变了柱状劈裂破坏是花岗岩在单轴压缩应力作用下自身所固有的破坏模式,使破坏模式逐渐向剪切滑移发展。花岗岩的纵波波速、杨氏模量和相对杨氏模量随着温度的升高均呈指数函数减小,纵波波速损失率随着温度的升高均呈幂函数增加,峰值应力、相对峰值应力、轴向峰值应变和相对轴向峰值应变随着温度的升高均呈logistic函数增大,这一变化趋势与自然状态的花岗岩力学性能随温度的变化趋势一致。HNO3溶液加剧了花岗岩的损伤劣化,而Na OH溶液对花岗岩的损伤劣化有一定的抑制作用,但随着温度的升高,这种抑制作用逐渐减弱,甚至消失,反而促进花岗岩的损伤劣化。(4)从细观力学和化学机理出发,分析了高温、化学浸泡、冻融循环及化学-温度-应力耦合作用下花岗岩的损伤机理,得出温度应力及化学反应使岩石内部结构和矿物成分发生改变,宏观上表现为力学性能的损伤劣化。通过定义损伤变量,定量分析了化学-温度-应力耦合作用下花岗岩的损伤程度。本文依据试验研究成果,总结了温度变化、化学溶蚀、冻融循环和化学-温度-应力耦合作用等因素对岩石的力学性能损伤、变形和破坏的规律。这一问题的研究对解决目前岩石工程的许多现实问题和文物保护有重要的指导作用。
[Abstract]:The geological conditions of rock are very complicated, and the influence of chemical, temperature and stress is very significant in many factors that affect the rock failure. In this paper, a series of related mechanical tests are carried out on the granite with the interaction of chemical temperature and stress, and the change law of the mechanical properties of rocks under polyinin and the damage machine are analyzed. According to the single factor, the influence of multiple factors on the mechanical properties of rock is gradually studied. Therefore, this paper mainly studies the following four aspects: (1) the failure modes of granite under uniaxial compression are analyzed by studying the mechanical properties of granite at the high temperature of ~800 C at 20 C in the natural cooling (in the furnace) and in the water. The influence of temperature and cooling mode on the mechanical properties of granite is discussed from the aspects of longitudinal wave velocity, stress strain curve, peak stress, axial peak strain, radial peak strain, Young's modulus and microstructure. The experimental results show that the longitudinal wave velocity of granite, peak stress and Young's modulus attenuate with the increase of experienced temperature. It shows that the speed of rapid cooling is greater than that of natural cooling. This shows that the higher the temperature, the worse the mechanical properties of granite, the deterioration of the mechanical properties of granite resulting from rapid cooling in water. The peak strain after rapid cooling in granite water is less than the peak strain after the natural cooling, indicating the granite in the high temperature state. After rapid cooling of rock water, its brittleness is more significant than that after natural cooling. (2) by studying the mechanical properties of granite after soaking in different chemical solutions (water, Na OH solution and HNO3 solution) and after freezing and thawing cycle, the corrosion of granite in different chemical solutions and the different cycles of freezing and thawing cycle have been analyzed under uniaxial compression. The experimental results show that in water, Na OH and HNO3 solutions, with the increase of the number of freezing and thawing cycles, the longitudinal wave velocity, Young's modulus, Young's modulus and peak stress of the granite decrease exponentially, both the longitudinal wave velocity loss rate and the peak stress loss rate increase with the power function, and the axial peak strain is Guass. The change of function.HNO3 has a serious influence on the fracture morphology of granite, but the effect of Na OH is weaker. With the increase of the number of freezing and thawing cycles, the early damage deterioration of granite with HNO3 solution is larger and the later damage deterioration is smaller, while the initial damage deterioration of granite with Na OH solution is smaller, and the later damage deterioration is larger. (3) through the study The mechanical properties of granite after chemical temperature stress coupling (i.e. water, Na OH solution and HNO3 solution and freezing thawing cycle, high temperature action and uniaxial compression) were studied. The change law of basic mechanical properties of granite after chemical temperature stress coupling was analyzed. The degree has a certain influence on the failure mode, which mainly shows that the failure mode of the columnar splitting is the inherent failure mode of the granite under the uniaxial compression stress, which makes the failure mode develop gradually to the shear slip. The longitudinal wave velocity of granite, the young's modulus and the relative Young's modulus are exponentially function with the increase of temperature. As the temperature rises, the rate of longitudinal wave velocity loss increases with the increase of the temperature, the peak stress, the relative peak stress, the axial peak strain and the relative axial peak strain increase with the increase of the temperature, which is consistent with the tendency of the natural state of the granite force with the temperature change, which is consistent with the.HNO3 solution plus the temperature. The damage deterioration of granites is deteriorated, and the Na OH solution has a certain inhibition effect on the damage and deterioration of granite. But with the increase of temperature, this inhibition gradually decreases and even disappears, but promotes the deterioration of the granite. (4) from the micromechanics and chemical mechanism, the high temperature, chemical soaking, freezing and thawing cycle and chemical temperature are analyzed. The damage mechanism of granite under the coupling of degree and stress is obtained. It is concluded that the temperature stress and chemical reaction make the internal structure and mineral composition of the rock change, and the damage deterioration of the mechanical properties is expressed in macroscopic view. By defining the damage variable, the damage degree of the granite is quantitatively analyzed by the chemical temperature stress coupling. The research results have summarized the laws of damage, deformation and destruction of rock mechanical properties, such as temperature change, chemical dissolution, freezing thawing cycle and chemical temperature stress coupling effect. The study of this problem has a important guiding role to solve many practical problems of rock engineering and the protection of cultural relics.
【学位授予单位】：上海理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU45

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