In order to study the effect of high temperature cycling on the physical and mechanical properties of rock materials, a box-type resistance furnace was used to conduct high temperature cycling at 400°C 10 times on sandstone specimens in coal mine, and the impact compression tests under 8 loading rates were carried out using a split Hopkinson bar (SHPB) device. Results showed that, with the increase of cycle times, the gray white sandstone specimen gradually showed reddish brown spots, and the volume of specimen increased, while the mass, density, and longitudinal wave velocity decreased; in addition, the volume increase rate, the mass decrease rate, the density decrease rate, and the longitudinal wave velocity decreased rate with cycle times showed quadratic function relationship. The dynamic compressive stress-strain curve of sandstone specimens subjected to high temperature cyclic action under impact load was obviously different from that under normal temperature. The dynamic elastic modulus was obviously larger than that under static load. The failure mode of dynamic and static specimens showed brittleness and ductility characteristics, respectively. In the SHPB test, the impact pressure, reflected energy, transmitted energy, and absorbed energy of the rock specimen all increased linearly with the increase of incident energy. The dynamic compressive strength, elastic modulus, and strain rate of sandstone specimens were positively correlated with the incident energy, while the dynamic strain showed negative correlation.

中文翻译：

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高温循环后砂岩的动态力学性能和耗能分析

为了研究高温循环对岩石材料物理力学性能的影响，采用箱式电阻炉对煤矿砂岩标本进行400℃高温循环10次，并进行冲击压缩。使用分体式霍普金森棒（SHPB）设备在8种加载速率下进行测试。结果表明，随着循环时间的增加，灰色白色砂岩试样逐渐显示出红褐色斑点，试样体积增加，质量，密度和纵波速度减小。另外，体积增加率，质量减少率，密度下降率和纵波速度下降率随循环时间呈二次函数关系。冲击载荷作用下高温循环作用下砂岩试样的动态压应力-应变曲线与常温下明显不同。动弹性模量明显大于静载荷下的动弹性模量。动态和静态样品的破坏模式分别显示出脆性和延展性。在SHPB测试中，岩石试样的冲击压力，反射能量，传输能量和吸收能量都随入射能量的增加而线性增加。砂岩试样的动态抗压强度，弹性模量和应变率与入射能量呈正相关，而动态应变呈负相关。