选取软弱砂岩为研究对象,利用RLW-2000M型三轴流变试验机,测试砂岩试样的轴向应力-应变、轴向流变变形、径向流变变形,研究了动荷载频率和幅值对砂岩流变特性的影响;选取轴向应变为损伤变量,推导出损伤度的计算表达式,分析了各因素对损伤度的影响特性。研究结果表明:在动态荷载作用下,轴向与径向变形随着时间的推移而增大,滞回曲线会由稀疏变稠密;轴向、径向变形增量随动载幅值的增大而增大,而随着频率的增大呈减小的趋势;试样的损伤度在突变后趋于稳定,且随着动载幅值的增大而增大。研究结论为揭示动态荷载作用下细砂岩流变损伤演化规律提供科学依据。

In this paper the axial stress-strain relation, the axial rheological deformation and radial rheological deformation of soft sandstone are measured by RLW-2000M triaxial rheological testing machine in an attempt to investigate the influence of frequency and amplitude of dynamic loading on sandstone’s rheological properties. Moreover, the expression of damage degree with axial strain as damage variable is derived, and the effect of each factor on damage degree is studied. Research results indicate that axial and radial deformations increase with the passage of time, and the hysteresis curve changes from sparse to dense under the action of dynamic loading. The increases in axial and radial deformations intensify with the climbing of dynamic loading amplitude, but attenuate with the rising of frequency. In addition, after an abrupt change, the damage degree of specimen tends to be stable and increases with the climbing of dynamic loading amplitude. The research results will provide scientific basis for us to uncover the rule of rheological damage evolution of sandstone under the action of dynamic loading.