摘要
采用SHPB动力学试验台对不同裂隙倾角红砂岩试件进行冲击试验,并对岩石破碎后的质量-粒径分布进行记录以及计算分形维数,分析其冲击载荷下的破碎分形特征及能量耗散规律.结果表明:在相同的冲击荷载作用下,随着裂隙倾角的增大,动态抗压强度增大,应变率减小,且倾角从45°增大到60°时,动态抗压强度增大最为明显;岩样中预制裂隙的存在会阻碍应力波的传递,导致反射能量增大,透射能量减小.并且,随着倾角的增大,预制裂纹的影响会逐渐减弱,而反射能和透射能不断减小,耗散能几乎不受裂纹倾角的影响;裂隙岩体分形维数随裂隙倾角和动态抗压强度的增大而线性增大,随应变率的增大而减小.分形维数与岩石破碎耗散能之间的关系满足幂函数关系.
Abstract
SHPB dynamic test bed was used to carry out impact tests on red sandstone samples with different fracture dips,recording the mass-particle size distribution after rock fragmentation and calculating its fractal dimension,to analyze the fractal characteristics of rock crushing and the law of energy consumption under impact load.The results show that:Under the same impact load,the dynamic compressive strength increases and the strain rate decreases with the increase of the crack dip angle,and the dynamic compressive strength increases most obviously when the dip Angle increases from 45° to 60°;The existence of prefabricated cracks in rock samples will hinder the transfer of stress waves,leading to the increase of reflection energy and the decrease of transmission energy.Moreover,with the increase of inclination Angle,the influence of prefabricated cracks will be gradually weakened,while the reflection energy and transmission energy will be continuously reduced and the dissipated energy will be almost not affected by the inclination Angle of cracks;The fractal dimension of fractured rock mass increases linearly with the increase of fracture dip angle and dynamic compressive strength and decreases with the increase of strain rate.The relationship between fractal dimension and rock-crushing dissipation energy satisfies the power function.
维普
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