利用带轴向静压和围压装置的霍普金森压杆设备,对砂岩在不同围压卸载条件下的动态力学性能进行试验研究,即保持轴压和冲击条件不变,改变围压卸载速度的动静组合冲击试验,着重研究了围压卸载速率对岩石动态强度及损伤的影响。实验结果表明：在仅改变围压卸载速度条件下,当卸载速度在0.5～10 MPa/s范围内变化时,砂岩动态抗压强度、能耗密度随围压卸载速度增大而降低;破坏块度分维数则呈现出随围压卸载速度增大而增大。但当卸载速度增大到200 MPa/s时,其动态抗压强度、能耗密度反而增加,而破坏块度分维数则降低。“,”By means of the improved SHPB with axial pre-pressure and confining pressure,experimental studies on the dynamic mechanical properties of sandstone under different unloading confining pressures are performed.In the experiments,the sandstone specimens are