脉冲射流割缝技术在石门揭煤中的应用研究

Investigation of a Self-Excited Pulsed Water Jet for Rock Cross-Cutting to Uncover Coal

针对西南地区煤矿石门揭煤周期长,严重制约了煤矿安全生产和采掘工作面接替等问题,提出了利用自激振荡脉冲水射流在煤层中割缝,增加煤层透气性,提高瓦斯解吸率,缩短石门揭煤时间的新思路.研究了高压脉冲水射流自激振荡的形成机理及其特性;通过实验室试验研究供水压力、流量等因素与切槽深度、宽度的关系,优化了自激振荡喷嘴结构及高压脉冲水射流的水力参数.通过在重庆逢春煤矿+523S4机轨巷揭M8煤层应用表明,使用自激振荡脉冲水射流割缝在煤层中的影响范围可达1.5m以上,增大了煤层瓦斯解吸能力,瓦斯释放量提高了4.4倍,钻孔数量减少了60%,缩短工期达70d以上,提高了工效.

Safe production and procedures at the driving face are restricted in mines of southwest China by the long periods required for uncovering coal by rock cross-cuts. A new idea is proposed to solve this problem using self-excited oscillations of pulsed water jets. This is proposed to improve the permeability of the seam and increase the gas desorption rate, which will shorten the cycle of rock cross-cutting and coal uncovering. The properties of a self-excited oscillating pulsed water jet were studied. The hydraulic parameters of the jet and the nozzle structure were optimized by investigating how pump pressure and flow rate effect the depth and width of slotting. Application at the Fengchun coal mine shows that the jet may penetrate 1.5 m or more into the coal seam and that the gas desorption rate increases by 4.4 times. Production efficiency is increased by reducing the number of holes drilled （by 60%） and reducing the construction period for uncovering cross-cut coal by more than 70 days.