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应力渗流耦合是岩石力学基本问题之一。以砂岩为研究对象进行不同排水条件下(排水和不排水)的三轴压缩试验研究。结果表明:围压对岩石有强化约束作用,岩石的弹性模量、峰值强度、启裂应力及扩容应力随围压增加而增大;在排水条件下,孔压一定程度上减弱了围压作用,弱化岩石的力学特性,且对黏聚力影响比对内摩擦角更加敏感;对于不排水条件,孔压变化峰值应力出现在扩容应力附近,是岩石内部裂纹开启的反映;同一初始孔压下围压越高相应孔压变化值越大,围压相同时初始孔压越大,其孔隙水压力变化越显著;同一围压下,不排水条件试验的岩石峰值强度、闭合应力、启裂应力和扩容应力一般低于排水条件下各项指标值。
Stress-seepage coupling is one of the basic problems of rock mechanics. Sandstone as the research object under different drainage conditions (drainage and undrained) triaxial compression test. The results show that the confining pressure has an intensive restraining effect on the rock, and the elastic modulus, peak strength, cracking stress and dilatancy stress increase with the increase of confining pressure. Under the drainage condition, the pore pressure weakens the confining pressure to a certain degree , Which weakens the mechanical properties of rock and is more sensitive to cohesion than to internal friction angle. For undrained conditions, the peak stress of pore pressure appears near dilatancy stress, which is the reflection of open crack in rock; The higher the confining pressure is, the larger the change of pore pressure is. The larger the initial confining pressure is, the more obvious the pore water pressure changes. Under the same confining pressure, the rock peak strength, closing stress and cracking stress And expansion stress is generally lower than the drainage conditions of the indicators.