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针对高瓦斯煤层煤巷掘进工作面钻屑敏感指标值较大、掘进困难等问题,利用高压液态CO_2致裂器掘进头短钻孔预裂消突技术,通过理论分析和现场试验手段研究发现:采用高压CO2致裂器在掘进头进行短钻孔预裂爆破,可以促进煤层裂隙发育,提高煤层透气性,降低瓦斯解吸指标,提高钻孔瓦斯抽采量,达到掘进头消突的目的。现场试验数据显示:致裂后钻屑瓦斯解吸指标△h2最大值为150 Pa,钻屑量S值也相对减小,达到消突目的。致裂后4 h内钻孔瓦斯抽采量超过未进行致裂时抽采量的2倍,短时间内煤层瓦斯含量降低,有效保证了煤巷掘进头安全快速掘进。
Aiming at the problems such as large sensitive index value of drill cuttings, difficult excavation and so on, the use of high-pressure liquid CO_2 fracturing head excavation head short bore pre-cracking elimination technology, through theoretical analysis and field test found that: The use of high-pressure CO2 fracturing in the boring head short-bore pre-cracking blasting can promote the development of coal seam fissures, improve gas permeability, reduce gas desorption index, improve gas drainage boreholes, head excavation to achieve the purpose. Field test data show that the maximum value of gas desorption index △ h2 after fracturing is 150 Pa, and the amount of drill cuttings S also decreases relatively, reaching the goal of elimination. Within 4 h after fracturing, the gas drainage volume of boreholes exceeds twice that of the non-fracturing gas, and the gas content of the coal seam decreases in a short period of time, which effectively ensures the safe and fast excavation of the coal tunnel boring head.