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为研究砂岩试件冲击载荷作用下的破碎能量耗散特征,利用变截面分离式Hopkinson压杆(SHPB)试验装置,采用3种冲击气压对煤矿砂岩试件实施不同加载速率的冲击压缩试验,分析试验中试件能耗规律。结果表明:砂岩试件吸收能量与入射能量之比相对恒定;试件破碎耗能密度与入射能量呈线性正比关系,而与试件平均应变率呈乘幂关系,显示出较强的应变率相关性;破碎耗能密度越大,试件破碎程度就越剧烈,采用破碎块度平均粒径可以对试件破碎程度进行定量描述,其值随试件破碎耗能密度增大而减小;试件动态强度与破碎耗能密度之间表现出较强的对数关系,试件吸收能量主要耗散于岩石的损伤演化与变形破坏,采用破碎耗能密度能较好反映砂岩试件在外载荷作用下的强度本质特征。
In order to study the energy dissipation characteristics of crushing energy under the impact load of sandstone specimens, the impact compression tests of sandstone specimens at different loading rates were carried out with three kinds of impact pressures using a variable section split Hopkinson pressure bar (SHPB) Test specimen energy consumption law. The results show that the ratio of absorbed energy to incident energy of sandstone specimens is relatively constant. The energy dissipation density of specimens is linearly proportional to the incident energy, and is exponentially related to the average strain rate of the specimen, indicating a strong strain rate correlation The higher the crushing energy density, the more severe the specimen is broken. Using the average particle size of the crushing block, the degree of crushing of the specimen can be quantitatively described, and its value decreases as the crushing energy density increases. Dynamic strength and crushing energy consumption showed a strong logarithmic relationship between the absorption energy of the specimen mainly in the evolution of rock damage and deformation damage, the use of crushing energy density can better reflect the sand load in the external load test Under the intensity of the nature of the characteristics.