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为研究高地应力下再受动力扰动的岩石力学特性,利用改进的岩石动静组合加载SHPB试验装置,对红砂岩进行一维预应力状态下岩石的冲击力学特性试验。选取4个轴压水平,进行不同应变率下的动加载试验。研究结果表明:不同应变率下,岩样在破坏阶段出现“峰后塑性”、“应力跌落”、“应变回弹”三种类型,岩样的割线模量随轴压的增大先增大后减小;相同轴压下,岩样的动态抗压强度和单位体积吸收能随着应变率的增大而增大,分别呈现出指数函数关系和线性关系;相同应变率下,岩样的动态抗压强度和单位体积吸收能随着轴压的增大呈先增大后减小的趋势;无轴压条件下,岩样为拉伸破坏模式,有轴压条件下,岩样为剪切破坏模式。
In order to study the mechanical characteristics of rock subjected to dynamic disturbances under high ground stress, an improved SHPB test device was used to simulate the impact mechanical properties of red sandstone under one-dimensional prestress. Four axial compression levels were selected for dynamic loading tests at different strain rates. The results show that under different strain rates, the rock samples show three types of “post-peak plasticity”, “stress drop” and “strain rebound” Under the same axial pressure, the dynamic compressive strength and the unit volumetric absorption of rock samples increase with the increase of strain rate, showing an exponential function and a linear relationship respectively; the same Under the strain rate, the dynamic compressive strength and the unit volumetric absorption energy of rock samples firstly increase and then decrease with the increase of axial compressive stress. Under no axial compression, the rock samples are in the mode of tensile failure with axial compression Under the condition, the rock sample is the shear failure mode.