深部强采动工作面卸压瓦斯全生命周期分阶段精准治理方法

Precise staged control method for pressure-relief gas over full lifecycle of deep high-intensity mining working face

  • 摘要: 深部强采动条件下综放工作面卸压瓦斯涌出时空演化规律不明,传统高抽巷施工成本高、抽采效率低,目前针对从开切眼至终采的全时间尺度(即全生命周期)内,基于采动覆岩动态演化与瓦斯涌出阶段耦合关系的瓦斯分阶段精准治理研究尚显不足。针对上述问题,以王家岭矿307工作面为工程背景,对采用不同层位高位定向长钻孔替代高抽巷进行卸压瓦斯抽采的可行性进行验证,并提出了“分阶段、差异化”精准治理方法。① 建立了深部采动裂隙场“贯通−纵向−水平”三区渗透率分布模型,明确了水平渗透区为卸压瓦斯优势运移与富集区域。② 提出了采动卸压瓦斯涌出的全生命周期概念,依据顶板来压特征与瓦斯涌出动态耦合关系,将其划分为发生期、突发期、波动期和稳定期4个阶段,并明确了各阶段瓦斯来源构成、涌出特征及占比,为分阶段瓦斯精准治理提供了理论依据。③ 针对初采阶段(发生期和突发期)设计了“弓型”定向钻孔轨迹,实现对瓦斯升浮路径的精准拦截;针对正常回采阶段(波动期)构建了“高−中−低”多层水平定向长钻孔优化布置模式,从而对采动覆岩空间内的卸压瓦斯储运区实现全面覆盖。现场试验结果表明,该方法使工作面瓦斯抽采体积分数提升至8%以上,回风流瓦斯体积分数稳定控制在0.4%以下,有效解决了回风隅角瓦斯超限问题,实现了瓦斯抽采的精准可控。

     

    Abstract: Under deep high-intensity mining conditions, the spatiotemporal evolution pattern of pressure-relief gas emission in the fully mechanized top-coal caving working face is unclear, while traditional high-level drainage roadway construction is costly and exhibits low gas extraction efficiency. At present, research on staged precise gas control over the full time scale from the opening cut to mining termination (i.e., the full lifecycle), based on the coupling relationship between the dynamic evolution of mining-induced overburden and gas emission stages, remains insufficient. To address these issues, taking the 307 working face of Wangjialing Mine as the engineering case, the feasibility of replacing high-level drainage roadways with high-level directional long boreholes at different strata for pressure-relief gas extraction was evaluated, and a "staged and differentiated" precise control method was proposed. ① A permeability distribution model of the deep mining-induced fracture field with three zones of "penetrating–vertical–horizontal" was established, which clarified that the horizontal storage–transport zone was the dominant migration and enrichment area for pressure-relief gas. ② The concept of the "full lifecycle" of mining-induced pressure-relief gas emission was proposed, and based on the dynamic coupling relationship between roof weighting characteristics and gas emission, the process was divided into four stages: occurrence stage, bursting stage, fluctuation stage, and stable stage. The gas source composition, emission characteristics, and proportion of each stage were clarified, providing a theoretical basis for staged precise gas control. ③ For the initial mining stage (occurrence stage and bursting stage), a "bow-shaped" directional borehole trajectory was designed to achieve precise interception of gas buoyant migration paths; for the normal mining stage (fluctuation stage), a "high–middle–low" multi-layer horizontal directional borehole optimized layout was constructed to comprehensively cover the pressure-relief gas storage and transport zones within the mining-induced overburden space. Field test results showed that this method increased the extracted gas volume fraction of the working face to over 8%, stably controlled the gas volume fraction in the return airflow below 0.4%, effectively solved the problem of gas exceeding the limit in the return air corner, and achieved precise and controllable gas extraction.

     

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