中文摘要：

为了研究炸药在不同煤岩介质中爆破所产生的裂隙扩展和力学特征,提高深孔预裂爆破对低透气性煤层进行增透的效果,在实验室搭建爆破模拟试验系统,设计穿层钻孔和顺层钻孔2种不同的装药模式,以Froude比例法建立煤层深孔预裂爆破的试验模型,利用相似材料配比加工制备尺寸为50 cm×50 cm×50 cm的试样进行爆破模拟试验。通过超动态应变仪监测煤岩层的应变信号,利用高速摄像仪记录试样完整的裂纹萌生、扩展、贯通直至试样破坏的全过程,分析爆破载荷作用下试样的动态力学特性和裂纹扩展特性。研究发现,裂纹主要是由压缩波与卸载波共同作用形成的,裂纹扩展方向与炮孔轴线方向垂直;在煤岩介质中实施穿层钻孔爆破的爆破效果优于顺层钻孔煤层爆破效果,当爆破应力波从煤层入射到岩层后,出现反射拉伸波,反作用于煤体上,加剧煤岩不同爆破介质的破坏程度,促使爆破裂隙的扩展。研究成果可用于指导井下低透气性煤层深孔预裂爆破装药方式的选择,以提高瓦斯抽采效率。

英文摘要：

In order to stduy the crack extension and mechanical characters of explosive blasting in different layers of coal-rock media and to increase the permeability of coal seam of low permeability in the deep hole pre-splitting blasting,a blasting simulation test system was set up in the laboratory. Two different charging modes of drilling borehole,cross and down the seam,were designed. Deep hole pre-splitting blasting test model was built based on Froude proportion method and the samples with the size of 50 cm×50 cm×50 cm were prepared with the similar materials. Under the above conditions,blasting simulation tests were carried out. The strain signals of coal rock were monitored with the super dynamic strain gauge. The whole process from the crack initiation,expansion and breaking through to the destruction of samples was recorded with the high speed camera. The dynamic mechanical and crack propagation properties under blasting loading were analyzed. The results showed that the cracks were mainly formed by the interaction of the compression and unloading waves and the direction of crack propagation was perpendicular to axis direction of hole. The effect of drilling blasting with borehole cross the seam was better than that down the seam. When the blasting stress wave was from the coal seam to the rock,the reflected tension shock wave was arisen to react on coal seam,which resulted in the aggravated damage of different coal-rock media and prompted blasting crack extension.