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为解决单一坚硬突出煤层瓦斯抽采效率低、抽采达标时间长、影响生产接替等问题,在实验室对穿层预裂爆破增加坚硬煤层的裂隙贯通长度,提高煤层透气性进行了相似模拟试验。通过实验得出,对于穿层钻孔爆破,炸药在坚硬煤层中爆炸产生的裂纹较长并且贯通性强。通过分析认为,爆破应力波在坚硬煤层中传播不易被煤层吸收,当应力波传播到更加坚硬的岩层时,会产生波的反射,继续反作用于煤层促进了煤层裂隙的继续扩展,从而使煤层中的裂隙延长、贯通。最后,在赵固二矿二1煤层进行了穿层钻孔预裂爆破的现场试验,通过对爆破前后的钻孔抽采数据进行考察分析,得出爆破后的单孔平均瓦斯浓度比爆破前增加81.18%~91.79%,平均瓦斯抽采纯量增加3.50~6.07倍,取得了很好的增透效果。
In order to solve the problems of low gas drainage efficiency, long time of reaching the standard of pumping and production succession in a single hard and prominent coal seam, a similar simulation test was conducted in the laboratory to increase the crack penetration length of hard coal seam through pre-cracking blasting and improve the permeability of coal seam . The experiment shows that for the borehole blasting through a borehole, the explosives produced by explosions in hard coal beds have longer cracks and strong penetration. The analysis shows that the propagation of the blasting stress wave in the hard coal seam is not easy to be absorbed by the coal seam. When the stress wave propagates to the harder rock formation, wave reflection will occur and the continued reaction on the coal seam will promote the further expansion of the coal seam fracture, The cracks extend, through. Finally, a field test of pre-splitting blasting of stratified layer borehole was conducted in No.21 coal seam of Zhaogou No.2 Mine. Based on the investigation and analysis of borehole drainage data before and after blasting, the average single-hole gas concentration after blasting was found to be lower than that before blasting An increase of 81.18% ~ 91.79%, the average gas extraction purity increased 3.50 ~ 6.07 times, and achieved good penetration enhancement effect.