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高 魁,王 秘,乔国栋,等. 松软煤层底板爆破致裂增透模拟试验研究及应用[J]. 煤炭科学技术,2024,52(6):102−110. doi: 10.12438/cst.2023-0914
引用本文: 高 魁,王 秘,乔国栋,等. 松软煤层底板爆破致裂增透模拟试验研究及应用[J]. 煤炭科学技术,2024,52(6):102−110. doi: 10.12438/cst.2023-0914
GAO Kui,WANG Mi,QIAO Guodong,et al. Simulation test research and application of blasting and penetration improvement in the soft coal seam floor[J]. Coal Science and Technology,2024,52(6):102−110. doi: 10.12438/cst.2023-0914
Citation: GAO Kui,WANG Mi,QIAO Guodong,et al. Simulation test research and application of blasting and penetration improvement in the soft coal seam floor[J]. Coal Science and Technology,2024,52(6):102−110. doi: 10.12438/cst.2023-0914

松软煤层底板爆破致裂增透模拟试验研究及应用

Simulation test research and application of blasting and penetration improvement in the soft coal seam floor

  • 摘要: 针对松软煤层爆破增透钻孔施工困难,爆破增透产生的裂隙不发育且易于重新压实的问题,提出在底板岩层开展爆破作业,达到松软煤层增透进而增加瓦斯有效抽采时间的目的。为了监测跨界面应力波传播规律及煤层损伤状况,在实验室构建了物理模型并开展了煤层底板爆破相似模拟试验。同时使用数值模拟的研究方法对煤层底板爆破过程中煤、岩体内部的损伤及裂隙的演化过程进行补充。结果表明:松软煤层底板爆破裂纹沿爆破孔向四周岩体扩展,爆破孔位置和底板煤岩交界面以及煤层内部的破坏较为严重,产生跨界面损伤裂纹。爆炸应力波从松软煤层底板岩层传播到松软煤层时,岩体和松软煤体的交界面产生透射压缩应力波和反射拉伸应力波,透射波作用于松软煤体,使煤层裂隙增加;反射波反作用于岩体,在煤岩交界面形成交叉裂纹,使底板岩层裂隙和松软煤层裂隙贯通,有利于松软煤层的瓦斯垂向运移流动和卸压瓦斯抽采。潘一东煤矿现场应用表明,煤层底板爆破增透后瓦斯抽采纯量及其浓度快速上升,抽采纯量从0.06 m3/min提高到1.46 m3/min,增加了23.33倍;瓦斯浓度从爆破前的10.46%上升到45.50%左右,增加了3.34倍,并且长时间维持在较高水平。研究成果可为深部松软煤层瓦斯高效抽采提供理论基础和技术支持。

     

    Abstract: Aimed at the problems of difficult drilling construction of blast penetration, undeveloped fractures produced by blast penetration, and the fractures is easy to recompact in the soft coal seam, the blasting operations carried out in the floor was proposed to achieve the purpose of increasing the penetration of soft coal seams and thus improve the effectiveness of gas extraction. In order to monitor the cross-interface stress wave propagation pattern and the damage state of the coal seam, a physical model was constructed in the laboratory and a similar simulation test of coal seam floor blasting was carried out. Concurrently, the numerical simulation research method was employed to supplement the evolution of damage and fractures within the coal and rock during the blasting process of the coal seam floor. The results shown that, the blast cracks expanded along the blast hole to the surrounding rock mass in soft coal seam floor, causing more serious damage at the location of blast hole, the coal-rock interface of the floor, and within the coal seam, producing cross-interfacial damage cracks. When the explosive stress wave propagated from the soft coal seam base rock layer to the soft coal seam, the interface between the rock and the soft coal generated transmitted compressive stress wave and reflected tensile stress wave. Transmission waves acted on the soft coal to increase the fractures in the coal seam. Meanwhile, the reflected waves reacted on the rock, forming cross-cracks in the coal-rock interface, making the fractures of the rock floor and the soft coal seam penetrated, which was conducive to the vertical transport flow of gas in the soft coal seam and the extraction of pressure-relief gas. Field application at Pan Yidong coal mine shown that, the pure volume of gas extraction and its concentration increased rapidly after blasting the coal seam floor to improve the penetration. The pure volume of gas extraction increased from 0.06 m3/min to 1.46 m3/min, an increase of 23.33 times. Gas concentration surged from 10.46% before blasting to approximately 45.5%, an increase of 3.34 times, and remained at a high level for a long time. The research results can provide theoretical basis and technical support for efficient gas extraction from deep soft coal seams.

     

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