孔底间隔介质对岩体损伤规律研究

为研究孔底不同间隔介质装药条件下，爆炸荷载不同，对岩体损伤、炸药与岩体之间的能量传递影响。利用数值模拟软件ANSYS/Autodyn，基于JH-2本构，建立小比例单孔爆破模型，获取孔底不同间隔介质装药条件下，不同强度爆炸荷载作用下对岩体损伤的影响规律；计算现场混装炸药JWL状态方程，引入台阶爆破模型，获取减少药量，添加孔底间隔介质，对岩石细观损伤、应力变化、能量传递影响规律；借助图像处理手段，对不同装药条件下岩石损伤与破碎块度进行量化处理，对能量传递效果作出评价。研究结果表明：（1）炸药与岩石合理匹配会提高能量传递效率，爆热越高的炸药，释放能量越多，传递到岩石能量也越高。（2）孔底间隔装药条件下，炸药与岩体匹良好，间隔介质为水介质可提高损伤5%，匹配度较差时，水介质可提高损伤12%。（3）当减少药量，改变装药结构，合理添加孔底间隔介质，会达到与连续装药条件下相近损伤效果。研究可为工程设计中连续装药与孔底间隔装药条件下炸药选型提供参考。

The damage law of rock mass by hole bottom spacer medium

To investigate the effects of different explosion loads on rock damage and the energy transfer between explosives and rock under different spacing interval conditions at the bottom of the borehole, the numerical simulation software ANSYS/Autodyn was utilized alongside the JH-2 constitutive model. By establishing a small-scale single-hole blasting model, the impact of various explosion load intensities on stress change under continuous loading and different spaced interval medium loading conditions was obtained. The JWL equation of state for on-site emulsion explosives was calculated, and a step-by-step blasting model was introduced to examine the influence of reducing the amount of explosives and adding bottom hole interval mediums on microscopic rock damage, stress changes, and energy transfer. Image processing was applied to quantitatively analyze rock damage and fragmentation under different loading conditions, providing an evaluation of energy transfer effect. The study revealed that: (1) explosives with similar impedance to rock and higher detonation heat release more energy, which is then transferred to the rock with higher energy. (2) Under bottom hole interval medium loading conditions, water as a medium can increase damage by 5% for explosives with good impedance matching, and up to 12% for those with poor matching. (3) By reducing the amount of explosives and adding bottom hole interval mediums, as well as modifying the loading structure, a similar damage effect can be achieved as in the continuous loading case. The research provides a reference for selecting explosives under continuous and spaced interval loading conditions in engineering design.