中文摘要：

基于低渗透砂岩型铀矿床爆破增渗方法，以断裂动力学为基础，采用ABAQUS内嵌哑节点数值模块及编写的气楔型荷载程序，对爆炸冲击波荷载下岩石Ⅰ型微裂纹动态起始扩展和爆生气体的动态作用效果进行数值研究，以期得到优化的加载方式使得岩层整体渗透性得到提升。研究结果表明：（1）较长的冲击波上升沿持续时间可激活岩石中更多的Ⅰ型微裂纹动态起始扩展；（2）冲击波峰值压力越大，裂纹尖端动态能量释放率越大，反之越小，过大或过小的冲击波峰值压力均不利于岩石Ⅰ型微裂纹的动态起始扩展和爆炸能的充分利用；（3）对比爆生气体准静态与动态2种分析方法产生的结果，发现动态计算结果对于裂纹的持续扩展更加有利，同时也能更加合理地解释裂纹运动失稳现象。最后基于上述研究总结对爆炸荷载下深层岩体动态破裂过程的新认识。

英文摘要：

Numerical simulations of initial dynamic extension of microcracks of mode Ⅰ under shock wave loading of blasting using ABAQUS embedded with a numerical module of dummy nodes and a load subroutine of air wedge was carried out to investigate the blasting-enhanced permeability of low-permeability sandstone with uranium deposits（BEPUD）. The numerical results indicated that the longer duration of rise time of shock waves, the more microcracks were activated in rocks. High peak pressure of shock wave led to high release rate of dynamic energy at crack tips. The excessive or insufficient peak pressures of shock wave were not conducive for the initial dynamic extension of microcracks and fully consumption of explosive energy. In virtue of the comparison of results from the static and the dynamic numerical analysis under explosive gas load, more crack growth in the dynamic analysis was found than in quasi-static analysis. The dynamic analysis explained better the phenomenon of the movement of crack instability.