空孔形状对岩石定向断裂爆破影响规律的研究

利用新型数字激光动态焦散线试验系统，采用有机玻璃板试件进行模型试验，研究了含预制不同形状空孔对岩石定向断裂控制爆破的影响规律。试验结果表明：在定向断裂控制爆破中，设置菱形空孔更有利于实现精细化定向断裂控制爆破，可有效保证巷道周边眼爆破的成型效果；对比含3种不同形状空孔试件爆生主裂纹扩展速度可知，含菱形空孔的扩展速度最大，含圆形空孔的次之，含带刻槽圆形空孔的最低；含圆形空孔试件爆生主裂纹端部动态应力强度因子总体比含菱形和切槽圆形空孔试件爆生主裂纹端部动态应力强度因子大；主裂纹扩展中后期阶段，含菱形空孔试件爆生主裂纹端部动态应力强度因子相对较小。

Influence of empty hole shape on directional fracture controlled blasting of rock

Model experiments are conducted on polymethyl methacrylate (PMMA) materials to investigate the influence of empty holes with different shapes on directional fracture controlled blasting of rock. A new digital laser dynamic caustics is applied to obtain caustics patterns around empty holes. Experimental results show that the preset rhombic hole can achieve fine directional fracture controlled blasting and effectively ensure the forming effect of blasting around the roadway. By comparing the propagation velocity of blast-induced cracks in specimens containing empty holes with three different shapes, it is found that the velocity of blast-induced main crack in a specimen with a rhombic hole is the greatest, then the velocity in a specimen with a circular hole is followed, and the velocity in a specimen with a circular hole with groove is the lowest. The values of dynamic stress intensity factor (DSIF) at the tips of blast-induced main cracks in specimens with a circular hole are generally higher than that in specimens with a rhombic hole and a circular hole with groove. The values of DSIF in specimens with rhombic holes are relatively low during the middle and late stages of blast-induced main cracks propagation.