Fundamental study on strength of rock under high water vapor pressure

岩石的强度受密度、裂缝的形状和方向、加载的应变和应力速率、应力状态、温度和水的存在（汽相或液相）的影响，许多研究者指出，岩石的强度取决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岩石中的化学作用，诸如水的环境因素削弱了裂纹尖端处的应变结合并促进裂纹扩展，并且当超过应力强度因子时，裂纹速度随着水蒸气压力的增加而增加。查尔斯，克罗科斯基等。和水谷等人的实验结果表明，岩石在单轴压缩试验下的强度随大气中水蒸气压力的降低而增加。据此认为岩石的强度可能受围岩环境的控制 关于我们 在本研究中，为了考察非大气环境，即水、丙酮、乙醇、气相甲醇和作为应力腐蚀剂的氢气对岩石强度的影响，对熊本安山岩进行了单轴压缩试验和10^6 Pa蒸汽压范围内的圆盘试验<-3>。结果表明，熊本安山岩抗压强度和抗拉强度随水蒸气压的降低而增加，水是促进它们之间应力腐蚀的最有效介质。由于这些材料对压缩强度的影响程度与对拉伸强度的影响程度相同，因此认为在压缩和拉伸应力状态下的断裂机理几乎相同。最后指出，在氢、氩、氮、氧等无机气体环境中，岩石的强度是在相同水蒸气压力下的两倍。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