This paper studied the rock dynamic fracture propagation under impact loads elaborately with a determination method proposed to calculate crack propagation dynamic stress intensity factor (DSIF). By utilizing the split-Hopkinson pressure bar, the impact experiments with an improved single cleavage semi-circle (ISCSC) specimen were conducted to illuminate the dynamic crack propagation behaviour. Meanwhile, the fracture characteristics and crack propagation velocity were obtained by the crack propagation gauges. Coordinating experiments with a numerical approach, the crack propagation dynamic stress intensity factors were calculated by an experimental–numerical method with fractal theory. Then, a finite difference model was developed based on the tensile fracture softening damage criterion. With the analysis of numerical and experimental results, the crack propagation behaviour and mechanism of crack arrest were discussed sophisticatedly. The results demonstrate that the novel ISCSC specimen shows a definite advantage in determining crack propagation and arrest DSIF. Additionally, the crack arrest DSIF is larger than the average propagation DSIF with a sharp increase. Meanwhile, the numerical simulation results which agree well with the actual crack propagation illustrate that the crack arrest should be dominated by the compressive stress perpendicular to the crack path, and there were several arrest pauses existing in the transitory crack arrest process.

本文采用一种确定计算裂纹扩展动应力强度因子（DSIF）的确定方法，对冲击载荷作用下的岩石动态裂隙扩展进行了详尽的研究。利用分裂霍普金森压力棒，进行了改进的单裂半圆（ISCSC）试样的冲击实验，以阐明动态裂纹扩展行为。同时，利用裂纹扩展仪获得了断裂特性和裂纹扩展速度。与数值方法相协调的实验，通过分形理论的实验-数值方法计算了裂纹扩展的动态应力强度因子。然后，基于拉伸断裂软化破坏准则建立了有限差分模型。通过数值和实验结果的分析，详细讨论了裂纹扩展行为和止裂机理。结果表明，新型ISCSC试样在确定裂纹扩展和阻止DSIF方面显示出一定的优势。此外，裂纹止裂DSIF大于平均扩展DSIF，并且急剧增加。同时，与实际裂纹扩展相吻合的数值模拟结果表明，裂纹停止应以垂直于裂纹路径的压应力为主，并且在瞬时裂纹停止过程中存在多个停止停顿的现象。裂纹止裂DSIF大于平均扩展DSIF，并且急剧增加。同时，与实际裂纹扩展相吻合的数值模拟结果表明，裂纹停止应以垂直于裂纹路径的压应力为主，并且在瞬时裂纹停止过程中存在多个停止停顿的现象。裂纹止裂DSIF大于平均扩展DSIF，并且急剧增加。同时，与实际裂纹扩展相吻合的数值模拟结果表明，裂纹停止应以垂直于裂纹路径的压应力为主，并且在瞬时裂纹停止过程中存在多个停止停顿的现象。