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上覆灰岩回采工作面顶板瓦斯高效抽采

Efficient gas extraction from roof of overlying limestone stoping face

  • 摘要: 为探索灰岩顶板条件下的瓦斯赋存状态及抽采方案,开展了灰岩的X射线衍射实验,研究了灰岩的物理化学特性,分析了灰岩对顶板瓦斯赋存和瓦斯抽采的影响。以山西沁源常信煤矿90107工作面为工程背景,先用经验公式理论计算顶板“两带”高度,再结合3DEC数值模拟软件分析回采过程中顶板破坏形态及裂隙发育特征,根据顶板裂隙发育优势区设计高位定向钻孔瓦斯抽采方案,最后通过现场实测验证。研究表明:随着工作面的推进,顶板初次垮落步距为40 m,周期垮落步距为40 m,垮落带高度为11.4 m,裂隙带发育高度为50 m,裂隙发育优势区为11.4~25.0 m;现场实测发现上隅角和工作面瓦斯超限问题得到有效解决。抽采后,上隅角瓦斯浓度始终保持在0.8%以下,上隅角瓦斯浓度降幅最大可达87.5%。研究结果为相似灰岩地质条件下瓦斯高效抽采提供了参考依据。

     

    Abstract: In order to explore the gas storage state and extraction scheme under the conditions of limestone roof, X-ray diffraction experiments of limestone were carried out. The physicochemical properties of limestone were studied, and the influence of limestone on the roof gas storage and gas extraction was analyzed. The 90107 working face of Changxin Coal Mine in Qinyuan, Shanxi was used as the engineering background. The height of the "two belts" of the roof was calculated by empirical formula theory, and then the failure morphology and fracture development characteristics of the roof in the process of coal winning were analyzed in combination with 3DEC numerical simulation software. The gas extraction scheme of high-level directional drilling was designed according to the advantage area of roof fissure development and verified by on-site measurement. The study shows that with the advance of the working face, the initial collapse step width of the roof is 40 m, the cycle collapse step width is 40 m, the height of the caving zone is 11.4 m, the development height of the fractured zone is 50 m, and the advantage area of fissure development is from 11.4 m to 25.0 m. The on-site measurement finds that the problem of gas exceeding limit in upper corner angle and working face is effectively solved. After the extraction, the gas concentration in the upper corner gas remains below 0.8%, and the maximum decrease of gas concentration in the upper corner is 87.5%. The research results provide a reference for efficient gas extraction under similar limestone geological conditions.

     

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