In this paper, the mechanical response of saturated geological rock under tidal force is explored by poroelastic theory. First, we use the free energy formula of saturated rock under a tidal force to study the relatio...In this paper, the mechanical response of saturated geological rock under tidal force is explored by poroelastic theory. First, we use the free energy formula of saturated rock under a tidal force to study the relationships of pore pressure with stress, and stress with strain. Then we analyze the relationship between rock strain and tidal potential by the equilibrium differential equations of saturated rock under tidal force. Finally, we derive the physical relationship between the two parameters （pore pressure and tidal mean stress） of saturated rock and tidal potential. The relationship shows that：pore pressure is directly proportional with tidal potential, but tidal mean stress of saturated rock is inversely proportional with tidal potential. The ratio coefficient is related not only to the Lame coefficients of rock skeletons, but also to the Blot modulus. By using this model to analyze observational well water level of C-18 well which locates in Huili, Sichuan Province, the well level response coefficient （D） was estimated. This way, we derive the Skempton coefficient （B）, the coefficient A and C which refer to the response coefficients of pore pressure and tidal stress to tidal potential respectively. Then we compare the differences among each coefficient in coupling and uncoupling conditions. It shows that for saturated rocks, the response of stress and pore pressure to earth tides is a product of coupling, and it is necessary to take into account the coupling effect when we study the mechanical response. The model will provide the basis not only for the study of mechanics and hydrodynamics of well-confined aquifer systems, and the mechanics of faulting under tidal force, but also for quantitative research of the triggering mechanism of tidal forces.展开更多
利用MTS815 Flex Test GT岩石力学试验系统,经过岩体受力状态模拟、无水压岩体力学特性测试、水岩耦合试验等几个阶段试验,对砂板岩岩体力学特性的高空隙水压效应进行了试验研究。结果表明:砂板岩岩体强度与变形性能随水压升高而降低,...利用MTS815 Flex Test GT岩石力学试验系统,经过岩体受力状态模拟、无水压岩体力学特性测试、水岩耦合试验等几个阶段试验,对砂板岩岩体力学特性的高空隙水压效应进行了试验研究。结果表明:砂板岩岩体强度与变形性能随水压升高而降低,其中水压对黏聚力c的影响最大,对内摩擦角φ的影响甚微,对变形模量的影响居于二者之间。随着水压升高,岩体的黏聚力c急剧下降,当水压较高时,岩体可能完全丧失黏聚力;随着水压升高,变形模量E50和E0均有降低,两个参数的变化梯度相差不大。这些成果揭示了砂板岩岩体力学特性的高空隙水压力效应,并建立了主要力学参数预测模型,成果对于解决工程实际问题具有重要的参考价值。展开更多
在MTS815 Flex Test GT岩石力学试验系统上进行不同围压下砂板岩三轴压缩全过程试验,并测试破裂岩体试样峰后的天然含水状态强度。对试样破裂面施加4级动水压力和静水压力,分别获得天然含水状态和每级水压下破裂岩体试样的强度。试验结...在MTS815 Flex Test GT岩石力学试验系统上进行不同围压下砂板岩三轴压缩全过程试验,并测试破裂岩体试样峰后的天然含水状态强度。对试样破裂面施加4级动水压力和静水压力,分别获得天然含水状态和每级水压下破裂岩体试样的强度。试验结果及分析表明,水对破裂岩体强度影响的作用机制主要表现在饱和软化与水压弱化两方面,即饱和软化作用不随水压的增减而变化和水压力对强度的弱化作用随水压升高而线性增大;主要影响强度参数中的黏聚力,对内摩擦系数的影响较小;裂隙岩体中静水压力的弱化作用强于动水压力。试验与分析还获得水对裂隙岩体的饱和软化以及静水压力综合作用的定量表达,并对这些成果的工程应用进行讨论。展开更多
基金supported by R&D Special Fund for Public Welfare Industry of Ministry of Science and Technology(200808055 and 200808079),the People's Republic of ChinaScience Research Plan Project of Hebei Province(Z2009104)
文摘In this paper, the mechanical response of saturated geological rock under tidal force is explored by poroelastic theory. First, we use the free energy formula of saturated rock under a tidal force to study the relationships of pore pressure with stress, and stress with strain. Then we analyze the relationship between rock strain and tidal potential by the equilibrium differential equations of saturated rock under tidal force. Finally, we derive the physical relationship between the two parameters （pore pressure and tidal mean stress） of saturated rock and tidal potential. The relationship shows that：pore pressure is directly proportional with tidal potential, but tidal mean stress of saturated rock is inversely proportional with tidal potential. The ratio coefficient is related not only to the Lame coefficients of rock skeletons, but also to the Blot modulus. By using this model to analyze observational well water level of C-18 well which locates in Huili, Sichuan Province, the well level response coefficient （D） was estimated. This way, we derive the Skempton coefficient （B）, the coefficient A and C which refer to the response coefficients of pore pressure and tidal stress to tidal potential respectively. Then we compare the differences among each coefficient in coupling and uncoupling conditions. It shows that for saturated rocks, the response of stress and pore pressure to earth tides is a product of coupling, and it is necessary to take into account the coupling effect when we study the mechanical response. The model will provide the basis not only for the study of mechanics and hydrodynamics of well-confined aquifer systems, and the mechanics of faulting under tidal force, but also for quantitative research of the triggering mechanism of tidal forces.
文摘利用MTS815 Flex Test GT岩石力学试验系统,经过岩体受力状态模拟、无水压岩体力学特性测试、水岩耦合试验等几个阶段试验,对砂板岩岩体力学特性的高空隙水压效应进行了试验研究。结果表明:砂板岩岩体强度与变形性能随水压升高而降低,其中水压对黏聚力c的影响最大,对内摩擦角φ的影响甚微,对变形模量的影响居于二者之间。随着水压升高,岩体的黏聚力c急剧下降,当水压较高时,岩体可能完全丧失黏聚力;随着水压升高,变形模量E50和E0均有降低,两个参数的变化梯度相差不大。这些成果揭示了砂板岩岩体力学特性的高空隙水压力效应,并建立了主要力学参数预测模型,成果对于解决工程实际问题具有重要的参考价值。
文摘在MTS815 Flex Test GT岩石力学试验系统上进行不同围压下砂板岩三轴压缩全过程试验,并测试破裂岩体试样峰后的天然含水状态强度。对试样破裂面施加4级动水压力和静水压力,分别获得天然含水状态和每级水压下破裂岩体试样的强度。试验结果及分析表明,水对破裂岩体强度影响的作用机制主要表现在饱和软化与水压弱化两方面,即饱和软化作用不随水压的增减而变化和水压力对强度的弱化作用随水压升高而线性增大;主要影响强度参数中的黏聚力,对内摩擦系数的影响较小;裂隙岩体中静水压力的弱化作用强于动水压力。试验与分析还获得水对裂隙岩体的饱和软化以及静水压力综合作用的定量表达,并对这些成果的工程应用进行讨论。
