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为了研究水–岩耦合作用对辽西花岗岩力学性质的影响,采用MTS–815岩石力学试验系统,通过对花岗岩试样施加不同的围压和孔隙水压力,对其变形破坏过程进行试验研究,分析水–岩耦合作用下辽西花岗岩的有效峰值强度、扩容现象、残余强度、峰后强度及其参数的演化规律。研究结果表明,有效峰值强度折减系数随孔隙水压力增大近似呈线性增长,但变化斜率随着围压增大而逐渐减小。在围压较小时孔隙水压对有效强度折减系数有明显的影响,在围压较大而孔隙水压较小时,施加应力压缩孔隙喉道抑制了孔隙水压对试样的作用。扩容起点是致密岩体水岩耦合作用增强的特征点,围压使得试样的扩容起点发生滞后,而孔隙水压力使得扩容起点提前发生,扩容现象与水岩耦合作用相互促进。水–岩耦合作用下试样的残余强度为对应状态峰值强度的21%~35%,Hoek-Brown常数随着围压的增大呈非线性增长,其值为3.5~5.0。峰后段试样的似内摩擦角变化不大,似黏聚力随着应变软化参数的增加有逐渐减小的趋势,而相同应变软化参数对应的似黏聚力则随着孔隙水压力的增大而减小,且似黏聚力、孔隙水压和应变软化参数间的关系可用3次样条曲面进行描述。
In order to study the effect of water-rock coupling on the mechanical properties of western Liaoning granite, MTS-815 rock mechanics test system was used to study the deformation and failure process of granite samples by applying different confining pressure and pore water pressure. EFFECT OF ROCK COUPLING ON Efficient Peak Strength, Expansion Capacity, Residual Strength, Peak Back Strength and Parameters of Granites in Western Liaoning Province. The results show that the effective peak strength reduction coefficient increases linearly with the increase of pore water pressure, but the slope of change decreases with the increase of confining pressure. When the confining pressure is small, the pore water pressure has a significant effect on the effective strength reduction coefficient. When the confining pressure is large and the pore water pressure is small, the application of stress-compression pore throat suppresses the effect of pore water pressure on the specimen. The starting point of expansion is the characteristic point where the coupling of water and rock in dense rock mass is enhanced. The confining pressure causes the starting point of expansion of the sample to lag, while the pore water pressure causes the starting point of expansion to occur ahead of time. The residual strength of the sample under water-rock coupling is 21% -35% of the peak value of the corresponding state. The Hoek-Brown constant increases nonlinearly with the increase of confining pressure, and the value is 3.5-5.0. The internal friction angle of the post-peak specimen does not change much, and the cohesive force tends to decrease gradually with the increase of strain softening parameters. The cohesion corresponding to the same strain softening parameter changes with the pore water pressure Increase and decrease, and the relationship between cohesion, pore water pressure and strain softening parameters can be described by cubic spline surface.