含硬夹矸高瓦斯低透气性煤层多向聚能爆破技术研究

针对在含硬夹矸高瓦斯低透气性煤层开采时，一方面煤层瓦斯抽采困难，另一方面煤层中的坚硬夹矸难破碎的问题，开展含硬夹矸高瓦斯低透气性煤层多向聚能爆破研究。理论上，分析多向聚能装药对爆破的影响，引入多向聚能影响系数，计算得出了不同方向上裂隙的范围。通过相似模拟试验，验证了多向聚能爆破实际效果；利用LS-DYNA数值模拟软件，对不同装药方式爆破作用下煤与夹矸裂隙的发育特征及应力演化规律进行了数值模拟研究。研究结果表明:多向聚能爆破能够将爆破能量积聚在夹矸弱化和煤层增透的方向上，形成以导向裂隙为主，大量分支裂隙为辅的裂隙网，在夹矸弱化和煤层增透方向上的应力峰值分别为普通爆破的1.21倍和1.16倍。多向聚能爆破能够在提高破碎坚硬夹矸能力的同时提升煤体中裂隙的发育程度，从而大幅优化爆破效果。

Study on multi direction shaped charge blasting technology for coal seam containing hard dirt band with high gas and low permeability

In view of the difficulty of gas extraction in the coal seam on the one hand and the difficulty of crushing the hard dirt band in the coal seam on the other hand when mining in the coal seam containing hard dirt band with high gas and low permeability,the multi direction shaped charge blasting for this kind of coal seam was studied.In theory,the influence of multi direction shaped charge on the blasting was analyzed,then the influence coefficient of multi direction shaped charge was introduced,and the ranges of cracks in different directions were calculated.The actual effect of multi direction shaped charge blasting was verified by the similar simulation tests.The development characteristics of crack in the coal and dirt band and the stress evolution laws under the blasting effect of different charging modes were studied by using the LS-DYNA numerical simulation software.The results showed that the multi direction shaped charge blasting could accumulate the blasting energy in the directions of dirt band weakening and permeability enhancement of coal seam,and the crack network with the directional cracks as primary and large amount of branch cracks as supplement formed.The peak stress in the directions of dirt band weakening and permeability enhancement of coal seam was 1.21 and 1.16 times of that in the ordinary blasting respectively.The multi direction shaped charge blasting can not only improve the ability of crushing hard dirt band,but also improve the development degree of cracks in coal,thus optimize the blasting effect greatly.