不同孔间距抽采孔对深孔预裂爆破增透效果影响研究

Study on gas drainage boreholes with different space distances between boreholes affected to pre-cracking blasting enhancement effect of deep boreholes

为了研究不同孔间距抽采孔对深孔预裂爆破效果的影响,利用ANSYS有限元模拟软件,建立深孔预裂爆破影响范围物理模型,设计5种工况探讨不同孔间距抽采孔对深孔预裂爆破的影响效果;研究了不同孔间距抽采孔对爆破裂隙的扩展形态的影响,分析了抽采孔内壁质点位移及振动速度,最终确定合理的孔间距。模拟结果表明:孔间距为4 m时爆生主裂纹会贯穿经过抽采孔,抽采孔可能会出现塌孔现象。3~7 m的孔间距区间,随着孔间距的增大,抽采孔对煤体爆生裂纹的影响逐渐削弱;孔间距虽然对裂隙整体走势产生影响,但对于煤层整体的增透效果并未产生明显差异;确定深孔预裂爆破的预裂孔与抽采孔的最佳间距为5 m。

In order to study gas drainage boreholes with different space distances between boreholes,ANSYS finite element simulation software was applied to establish a physical model of a pre-cracking blasting influence range in a deep borehole. There were five operation performances designed to discuss the gas drainage boreholes with different space distances between boreholes affected to the pre-cracking blasting influence range in the deep borehole. The paper had a study on the gas drainage borehole with different space distances between boreholes affected to the expansion shape of the blasting cracking,an analysis on the point mass displacement of the inner wall in the gas drainage borehole and a final determination on the rational space distances between the boreholes. The simulation results showed that when the space distance between the boreholes was 4 m,the main cracking fractured would pass through the gas drainage borehole and the gas drainage borehole would have a collapse phenomenon occurred. When the space distance between the boreholes was ranging from 3 ~ 7 m,with the space distance between the boreholes increased,the gas drainage borehole affected to the cracking fractured in the seam would be steadily weaken. Although the space distance between the boreholes would be affected to the whole tendency of the cracking,but the whole permeability improved effect to the seam would not have obvious difference. The optimum space distance between the pre-cracking borehole and the gas drainage borehole with the ore-cracking blasting in the deep boreholes was 5 m.