中文摘要：

利用改进的霍普金森压杆对不同围压、不同应变率下的岩样进行了试验研究,分析了其在中高应变率下的冲击响应特征与破坏模式。基于试验结果发现在围压一定情况下,岩石的动态抗压强度和峰值应变随应变率的增大而增大,其中抗压强度随应变率呈对数增长;弹性模量对围压和应变率不敏感,且应变率越大岩石破碎现象越严重。其次,在应变率相近情况下,花岗岩的动态抗压强度随围压呈增大趋势,其破坏模式由低围压下的轴向劈裂转向高围压下的压剪破坏;高围压下花岗岩应力–应变曲线出现屈服平台,具有明显的脆—延性转化特征。最后,检验了莫尔–库仑准则和霍克–布朗准则的适用性,指出此花岗岩更符合莫尔–库仑准则,其动态强度增大主要由黏聚力的应变率效应引起。

英文摘要：

Experimental studies on the granite specimens under different confining pressures and strain rates are conducted using the improved split Hopkinson pressure bar（SHPB）, and the impact response and failure mode of the rock subjected to intermediate and high strain rates are analyzed. Based on the test data, it is revealed that the dynamic compression strength and the peak strain of the granite increase with the increasing strain rate under the same confining pressure, and there is a logarithmic relationship between the dynamic strength and the strain rate. The elastic modulus of the granite is insensitive to the confining pressure and strain rate. The larger the strain rate is, the more serious the rock breakage is. Then, it is found that the compression strength of the granite increases with the increase of the confining pressure when the strain rate is identical. The failure mode of such granite takes on a change from the axial splitting at lower confining pressure to the compression/shear failure under high confining pressure. The stress-strain curve of the rock has a yield platform, being an apparent brittle-ductile transformation characteristic. Finally, the applicability of the famous Mohr-Coulomb criterion and the Hoek-Brown criterion to the biotite granite is further examined. It indicates that the granite can be well described by the Mohr-Coulomb criterion. The increase of dynamic strength of the granite is primarily due to the rate effect of cohesion.