花岗岩和大理岩在不同应变率下的冲击试验研究

Impact experimental study of granite and marble under different strain rates

利用橡胶波形整形器改进后的分离式霍普金森压杆装置,对花岗岩和大理岩在不同应变率下进行了冲击压缩试验。通过试验有效性的验证,证明了数据的可靠性。试验结果表明:应变率明显影响这两类岩石材料的动态力学特性,不同冲击速度下的动态抗压强度、峰值应力、弹性模量表现出显著的率相关性,峰值应变则变化不大,其中分析了花岗岩和大理岩的峰值应力-冲击速度关系以及弹性模量-冲击速度关系,两者呈弱幂函数关系;加载过程中花岗岩表现出更显著的动态脆性,在破坏形态方面花岗岩大多呈轴向劈裂破坏,大理岩破碎程度明显更高呈压碎破坏,并从微观结构方面进行了对比分析。

Experiments with different strain rate on granite and marble under impact compressive loading are conducted with the modified split Hopkinson pressure bar. Through verifying the validity of the test,the reliability of the data is proved. The experimental results show that the strain rate obviously affects the dynamic mechanical properties of these two kinds of rock materials,the dynamic compressive strength,peak stress and elastic modulus with different impact velocities show significant strain rate correlation,peak strain changes little,the relationship between the peak stress-impact velocity and the elastic modulus-impact velocity of granite and marble is analyzed,and both of them show weak power function;In the process of loading,granite showed more obvious dynamic brittleness,from destruction form,most of the granite present axial splitting mode,the fragment degree of marble is higher and the marble present crushing mode,conducting the comparison and analysis from the perspective of microstructure.