装药结构对煤层深孔聚能爆破增透的影响

Effect of charge structure on deep-hole cumulative blasting to improve coal seam permeability

  • 摘要: 针对装药结构对聚能爆破煤层增透的影响,在分析装药结构对爆炸应力波传播特性、爆破裂隙分区影响的基础上,基于平煤十矿己组煤层瓦斯地质条件设计了煤层深孔聚能爆破现场试验方案,通过现场试验探讨了装药结构对煤层深孔聚能爆破在水平方向和竖直方向上的影响.实验结果表明:装药结构影响煤层深孔聚能爆破增透效果,煤层深孔聚能爆破后,在水平方向爆破影响区内瓦斯抽采浓度平均增幅为52.78%;竖直方向上距离爆破孔相同距离的考察孔在爆破后,处于爆破孔上方的考察孔无炮烟逸出,处于下方的考察孔有炮烟逸出,证明偏心不耦合装药结构对爆破孔上方煤层影响小于对下方煤层影响,爆破孔上方爆破裂隙范围小于下方爆破裂隙范围.

     

    Abstract: The charge structure is an important aspect of deep-hole cumulative blasting, and its influence on the blasting effect cannot be ignored; a reasonable charge structure can improve the rate of explosive energy utilization, thereby improving the blasting effect. In the study of the mechanism of deep-hole cumulative blasting in coal seam, the concentric decoupled charge structure is extensively analyzed. However, in the field test, the centers of the explosive charge and blast hole are offset because of the effect of gravity. Moreover, an eccentric decoupled charge structure is formed, which changes the decoupling coefficient around the blast hole and affects the blasting effect. This study focuses on the influence of the charge structure on improving coal seam permeability. The influence of the charge structure on the propagation characteristics of the explosion-induced stress wave and the partition of the explosion fracture was analyzed. A field experiment on coal seam deep-hole cumulative blasting was designed based on the gas geological conditions of the Ji group seam in Pingdingshan Coal Mine. Additionally, the influence of the charge structure on the horizontal and vertical directions of coal seam was discussed. Experimental results of deep-hole cumulative blasting in coal seam indicate that the charge structure has an influence on coal seam permeability. In the horizontal blasting area, the average increase in gas concentration is 52.78% after blasting. In the inspection holes located above and below the blast hole respectively, at a vertical distence of 1 m, after blasting, no blasting smoke escapes from the hole above the blast hole, but the blasting smoke escapes from the hole below the blast hole, which proves that the influence of the eccentric decoupled charge structure on coal seam below the blast hole is greater than that on coal seam above it. Moreover, the range of the fracture above the blast hole is smaller than that below the blast hole.

     

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