高压脉冲水射流提高松软煤层透气性的研究

Study on improving the permeability of soft coal seam with high pressure pulsed water jet

提出了利用高压脉冲水射流钻孔、切缝以提高松软煤层透气性和瓦斯抽采率的新思想.基于岩石动态损伤模型,理论分析和数值模拟了高压脉冲水射流瞬时动载荷、柔性撞击作用下煤体的动态损伤特性及裂隙场的变化规律.结果表明,高压脉冲水射流的冲击效应、剥蚀效应以及震动效应等冲击荷载作用可有效破碎煤体,增大煤体裂隙率和裂隙连通率,提高煤层透气性.研发出了低透气性煤层中的高压脉冲水射流瓦斯抽采系统,在重庆某典型高瓦斯低透气性煤矿进行了成功应用,应用结果表明,高压脉冲水射流有效提高了煤层透气性,平均百米钻孔煤层瓦斯抽放量较原工艺提高了7.8倍.

The new idea of improving the soft seam permeability and gas releasing rate by drilling and slitting the coal seam was presented. Based on the rock dynamic damage model, the dynamic damage properties and the fracture field＇ s dynamic evolution mechanism were studied by theory analyses and numerical simulation on the condition of instantaneous dynamic load and flexible impact of high pressure pulsed water jet. The results show that the impact effect, denudation effect and vibration effect are effective in the coal cracking and permeability improving. The gas drainage system of PWJ has been developed and applied successfully in a typical mine of rich gas and low permeability in Chongqing. The application demonstrates the high pressure pulsed water jet has effectively improved seam permeability with the drainage flux mounting to 7.8 times per 100 m of drainage hole.