【摘要】 文章用分离式霍普金森压杆(split-Hopkinson pressure bar, SHPB)装置对3种长径比的灰砂岩和红砂岩进行了冲击压缩试验,研究了2类砂岩在静、动荷载作用下抗压强度的尺寸效应。结果表明:随岩样长径比增加,2类砂岩的静态抗压强度均降低,而其动态抗压强度的增幅均增大,砂岩种类不同,尺寸效应的影响也不同;在高应变率下,尺寸效应不仅影响岩石的强度,也影响岩石应力-应变曲线的塑性段和破坏卸载段的变形特性。由于静、动荷载作用下尺寸效应对岩石力学行为的影响显著不同,必须采用相同尺寸岩样进行试验;而较短的岩样在动态试验中更容易受力均匀,惯性效应的不利影响较小,建议岩样长径比为0.5。更多还原

【Abstract】 Split-Hopkinson pressure bar(SHPB) is used to conduct impact compression test on grey and red sandstones with three length-diameter ratios. The size effect of compressive strength of two kinds of sandstones under static and dynamic loads is studied. First, as the increase of the ratio of length to diameter of rock specimen, the static strength of both types of sandstone decreases, while the increment of dynamic strength increases. The influences of size effect of grey sandstone and red sandstone are different. Second, under high strain rate, the size effect not only influences rock strength, but also influences the deformation characteristics of plastic region and post-failure region of rock stress-strain curve. Third, due to the influences of size effect on rock mechanical behaviors under static and dynamic load are significantly different, tests must be performed on rock specimens of the same size. And shorter rock specimens are easier to be loaded uniformly in dynamic tests, and the adverse effects of inertial effect are smaller. It is recommended that the length-diameter ratio of rock specimens is 0.5.更多还原