顶板巷卸压瓦斯抽采诱导遗煤自燃机理及扰动效应研究

The technique of using roof tunnel to drain the relieved gas is widely used in Chinese coal mines. However, this technique also easily brings the safety problems for underground coal production, such as coal spontaneous combustion in the mined-out area. Starting from the point of controlling coal spontaneous combustion with combing of case analyses, theoretical analyses, experimental researches, numerical simulations and field verifications, this project is going to study on the characteristics of transfixion between the development of coal rock and the roof tunnel during the mining process, and explain the formation mechanism of air leakage among the gob-overlying strata-roof tunnel effected with stress field environment. The oxygen migration seepage properties of the residual coal under the condition of the coupling among stress-temperature in gob and the permeability distribution characteristics are going to be studied by conducting experimental researches. The coupling disaster model of gas extraction and coal spontaneous combustion will be established. The relating factors that cause coal spontaneous combustion during the gas extraction in gob will be identified; The disturbance effects of quantity of methane drainage on the fields of flow pattern and oxygen in the gob will be analyzed. The major influences of changes to coal spontaneous combustion temperature and byproduct-gases under different drainage quantity of methane will be experimentally studied. Based on these research findings, the mechanism of spontaneous combustion and disturbance effects of residual coal induced by roof tunnel relieved gas extraction can be understood. The research results can contribute both in theory and practice to well mitigating the dilemma in gas extraction and coal spontaneous combustion control for gassy mines.

顶板巷卸压瓦斯抽采技术在国内广泛使用，然而易诱发采空区遗煤自燃，对矿井的安全生产构成威胁。本项目拟从煤自燃防治角度出发，通过案例调查、理论分析、实验研究、数值模拟及现场修正相结合的研究方法，研究采动过程中煤岩裂隙发育与顶板巷的贯通特征，阐述应力场影响下采空区-覆岩-顶板巷间漏风通道形成的机制；实验获得遗煤在“应力-温度”条件下氧气介质的渗透特性及采空区的渗透率的分布特征；建立瓦斯抽采与煤自燃的耦合致灾模型，识别瓦斯抽采过程诱导采空区遗煤自燃的致灾关联因素；掌握瓦斯抽采量对采空区流速场、氧气浓度场扰动效应，实验得到瓦斯抽采量对遗煤自燃温度及气体产生宏观影响。通过上述研究，获得顶板巷卸压瓦斯抽采诱导遗煤自燃机理及扰动效应，研究成果将对高瓦斯易自燃矿井协调瓦斯抽采与煤自燃防治具有重要的理论及现实意义。

本项目基于采空区顶板巷卸压瓦斯抽采对遗煤自燃扰动的问题，研究了采空区顶板巷瓦斯抽采诱导遗煤自燃效应及规律。掌握了采动过程中煤岩裂隙发育与顶板巷的冒落破断特征；阐述了应力场影响下采空区-覆岩-顶板巷间漏风通道形成的机制；实验研究了遗煤在“应力-温度”条件下气体的渗透特性；建立了瓦斯抽采与煤自燃的耦合致灾模型，识别瓦斯抽采过程诱导遗煤自燃的致灾关联因素；掌握了顶板巷瓦斯抽采量及空间参数对采空区流速场、氧气浓度场的扰动效应。.具体结论如下：1)顶板巷滞后采空区具有一定的距离，与覆岩冒落、裂隙发育和顶板巷的高度有关；2)顶板巷瓦斯抽采下，采空区漏风呈现“一源两汇”的特征，采空区漏风呈现高位漏风与低位漏风的立体特征；3)因顶板巷的层位关系，易在采空区内部形成内生热风压，恶化漏风；4)瓦斯抽采量加大，有助于降低瓦斯超限，但采空区氧化区域宽度加大；增大顶板巷垂直高度有助于瓦斯抽采但不利于防火；增大内错距离不利于瓦斯抽采但利于自燃防治；5)建立了合理瓦斯抽采量模型，对一特定的工作面，合理瓦斯抽采量与工作面瓦斯绝对涌出量、煤层自然发火期、工作面推进速度以及煤耗氧特性有关。.通过研究，本项目揭示了顶板巷瓦斯抽采下的漏风形成机制、顶瓦斯抽采量及空间布置参数对采空区煤自燃的扰动效应。建立了合理瓦斯抽采量理论模型、掌握了采空区瓦斯抽采与煤自燃互动影响过程。这项研究对协调顶板巷瓦斯抽采与煤自燃协同防治具有重要的理论及现实意义。