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采用MTS伺服刚性压力实验机对高家梁煤矿泥岩进行了三轴蠕变实验研究,获得了泥岩在不同应力条件下的蠕变变形规律。实验表明围压对泥岩微观缺陷的发展有一定的限制作用。随着围压的增加,泥岩的三轴抗压强度和弹性模量均有所增加。在围压一定时:衰减蠕变量随轴压的增大而增大;衰减蠕变率随偏应力的增加而增大;稳态蠕变率随偏应力的增大而增大。在偏应力一定时,稳态蠕变率随围压的增大而减小。当围压大于4MPa后,围压的限制作用将明显减小。随着围压继续增大,稳态蠕变率变化并不明显。根据获得的实验数据,用回归法求出了H-K模型蠕变方程的参数。结果表明H-K模型能较好地模拟实验结果。在实际工程中可通过支护增加围压以提高围岩屈服强度,也可根据实际工程中泥岩蠕变的变化趋势确定合理的二次支护时间,避免流变破坏的发生。
The MTS servo rigid pressure test machine was used to study the triaxial creep of the mudstone in Gaojialiang coal mine, and the creep deformation law of the mudstone under different stress was obtained. Experiments show that confining pressure has a certain limiting effect on the development of micro-defects in mudstone. As the confining pressure increases, the triaxial compressive strength and elastic modulus of mudstone increase. When the confining pressure is constant, the creep attenuation decreases with the increase of axial compression; the creep decay rate increases with the increase of deviatoric stress; and the steady creep rate increases with the increase of deviatoric stress. When the deviatoric stress is constant, the steady state creep rate decreases with the increase of confining pressure. When confining pressure is more than 4MPa, confining pressure will be significantly reduced. As confining pressure continues to increase, steady-state creep rate changes are not obvious. Based on the experimental data obtained, the parameters of the creep equation of H-K model were obtained by regression method. The results show that the H-K model can better simulate the experimental results. In actual engineering, the confining pressure can be increased by supporting to increase the yield strength of surrounding rock. The reasonable secondary support time can also be determined according to the change tendency of mudstone creep in the actual project to avoid the occurrence of rheological damage.