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利用自主研发的煤岩剪切-渗流耦合试验装置,开展了渗透水压作用下完整砂岩试件剪切-渗流耦合特征试验研究。结果表明:(1)在恒定渗透水压情况下,法向应力越大,砂岩的抗剪强度越高,法向变形则越小,砂岩的剪切变形过程可分为3个阶段:剪切变形的线性增长阶段、非稳定破裂发展阶段和剪断后的摩擦滑移阶段;(2)在恒定渗透水压情况下,法向应力越小,法向和剪切变形量越大,剪切断面的起伏程度越大,表面次生裂纹发育越明显、发育范围越宽,砂岩的破坏程度越严重;(3)在整个剪切过程中,剪应力出现几次明显的应力降,首次应力降出现在线弹性变化末期,同时伴有水流流出,说明首次应力降是第一条宏观贯通的裂纹所致,且法向应力越大,裂隙越窄,导水能力越差。
By using the self-developed coal-rock shear-seepage coupling test device, the experimental study on shear-seepage coupling characteristics of intact sandstone specimens under the action of infiltration hydraulic pressure is carried out. The results show that: (1) Under the condition of constant infiltration pressure, the larger the normal stress is, the higher the shear strength of sandstone is and the smaller the normal deformation is. The shear deformation process of sandstone can be divided into three stages: shear The stage of linear growth of deformation, the stage of unstable fracture and the stage of friction and slip after shearing; (2) In the case of constant seepage pressure, the smaller the normal stress, the greater the normal and shear deformation, (3) In the whole shearing process, there are several obvious stress drop in shear stress, and the first stress drop appears At the end of the online elastic change, with the outflow of water, it shows that the first stress drop is caused by the first macro-through crack, and the larger the normal stress, the narrower the crack and the poorer the water conductivity.