Fundamental study on strength of rock under high water vapor pressure

岩石的强度受密度、裂纹的形状和方向、加载的应变和应变率、应力状态、温度以及气相或液态水的存在等因素的影响。许多研究表明，岩石的强度依赖于应力腐蚀引起的亚临界裂纹扩展，应力腐蚀裂纹扩展是由于水等环境介质的化学作用削弱了裂尖的应变结合，促进了裂纹的扩展，裂纹速度超过了应力强度因子，应力腐蚀极限随着水蒸气压力的增加而增加。查尔斯，克罗科斯基等人。和水谷等人。试验结果表明，岩石单轴压缩强度随大气中水蒸气压力的降低而增大。据此认为，岩石的强度可能受ROC…周围环境的控制。为了考察非大气环境，即水、丙酮、乙醇、气相中的甲醇和氢作为应力腐蚀剂对岩石强度的影响，对熊本安山岩进行了水蒸气压力在10^~10^6帕范围内的单轴压缩试验和圆盘试验。实验结果表明，熊本安山岩的抗压和抗拉强度随着水蒸气压力的降低而增加，水是促进其中应力腐蚀的最有效的介质。由于这些材料对抗压强度的影响程度与对抗拉强度的影响程度相同，因此认为压应力状态和拉应力状态下的断裂机理基本相同。结果表明，在氢气、氩气、氮气和氧气等无机气体环境下，岩石的强度是相同水蒸气压力下的两倍。较少

The strength of rocks is affected by the density, the shape and the direction of cracks, the strain and stress rate of loading, the stress state, the temperature and the existence of water in vapor phase or in liquid phase, and so on. Many researchers have indicated that the strength of rocks is dependent on the suberitical crack growth due to stress corrosion.The stress corrosion crack growth occurs because the chemical action of an environmental agent, such as water, weakens the strained bonded at crack tips and facilitates crack propagation, and the crack velocity as a stress intensity factor is exceeded the stress corrosion limit increases with increasing water vapor pressure. Charles, Krokosky et at. and Mizutani et al. have shown the experimental results that the strength of rocks under uniaxial compression test increases with decreasing water vapor pressure in atmosphere. Accordingly, it is considered that the strength of rocks may be controlled by surrounding environment of roc … More ks, based on the above facts.In this research, to examine the influence of non-atmospheric environment, namely water, acetone, ethanol, methanol in vapor phase and hydrogen as the stress corrosion agent, on the strength of rock, uniaxial compression test and disc lest under the vapor pressure of the range from 10^<-3> to 10^6 Pa are conducted on Kumamoto andesite.From the experimental results, it is made clear that tie compressive and tensile strength of Kumamoto andesite increases with decreasing the water vapor pressure and that water is tie most effective agent which promotes the stress corrosion among them. Since the degree of influence of these materials on the compressive strength is the same as that on the tensile strength, it is considered that the mechanism of the fracture under compressive and tensile stress state is almost the same. Finally, it is shown that the strength of rock under inorganic gas environment, like hydrogen, Argon, nitrogen and oxygen, is two times as much as that under the same water vapor pressure. Less