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为研究含水率对岩石动态力学性能的影响,采用分离式霍普金森压杆(SHPB)装置对4种含水状态下长径比为0.5的两处煤矿砂岩实施单轴冲击压缩试验,获得相应状态下砂岩试件的动态应力–应变曲线。试验结果表明,在高应变率加载条件下,由于砂岩含水裂纹中自由水的表面张力作用和Stefan效应,产生了抑制裂纹动态扩展的阻力;且砂岩试件含水率越大,裂纹动态扩展阻力越大,砂岩的动态单轴抗压强度越高。拟合发现,砂岩动态单轴抗压强度随试件含水率呈幂函数增长。由于自由水充填了砂岩试件中的孔隙和微裂纹,砂岩试件纵波波速随含水率也呈幂函数增长。
In order to study the influence of water content on the dynamic mechanical properties of rock, uniaxial impact compression tests were carried out on two coal mine sandstones with the aspect ratio of 0.5 under four kinds of water-containing Hopkinson Pressure Bar (SHPB) devices to obtain the corresponding state Dynamic Stress-Strain Curves of Lower Sandstone Specimens. The experimental results show that under the condition of high strain rate, the resistance to the dynamic expansion of the crack is produced due to the surface tension of free water and the Stefan effect in the water-bearing sandstone sandstone. The larger the water content of the sandstone specimen, the more the dynamic crack propagation resistance Large, dynamic uniaxial compressive strength of sandstone is higher. The fitting shows that the dynamic uniaxial compressive strength of sandstone increases with the power of water content of the specimen. Since free water filled the pores and microcracks in sandstone specimens, the longitudinal wave velocity of sandstone specimens also increased exponentially with the water content.