【摘要】：針對西部礦區(qū)淺埋深、薄基巖和厚煤層的賦存特點和煤層開采過程中覆巖斷裂裂縫貫通地表并導致地表漏風,并由此引起工作面通風紊亂、采空區(qū)CO濃度超限、存在遺煤自燃隱患等影響安全生產(chǎn)的問題。本文以內(nèi)蒙古串草圪旦煤礦地質(zhì)賦存及生產(chǎn)技術條件為背景,從覆巖結構運動與空氣流動學的角度出發(fā),綜合采用現(xiàn)場實測、相似材料模擬、數(shù)值計算、理論分析、現(xiàn)場工業(yè)性試驗等研究方法,對淺埋厚煤層高強度開采條件下覆巖失穩(wěn)運動特征及斷裂裂縫的動態(tài)分布與發(fā)展變化規(guī)律、覆巖導氣裂縫的產(chǎn)生機理及其時空演化規(guī)律、導氣裂縫影響下采空區(qū)流場及工作面漏風特征等進行了系統(tǒng)深入地研究,提出了基于覆巖導氣裂縫控制的淺埋厚煤層開采安全保障技術。研究成果對于西部礦區(qū)淺埋厚煤層高強度開采巖層控制和安全生產(chǎn)具有重要的理論價值和現(xiàn)實意義�；诖蒇俚┟旱V淺埋厚煤層開采工程地質(zhì)條件,實測得出了不同埋深、覆蓋層厚度條件下工作面地表采動裂縫時空分布規(guī)律、動態(tài)發(fā)育特征及其主控因素,以及地表漏風強度、采空區(qū)氣體濃度分布規(guī)律及其相關關系。分析歸類了地表采動裂縫的類型及其對工作面安全生產(chǎn)的影響。建立了覆巖承載關鍵層深梁結構力學模型,得出了深梁結構承載關鍵層初次破斷和周期性破斷的破斷特征、失穩(wěn)運動形式及其影響因素,以及覆巖貫通型地裂縫的形成機理。分析了承載關鍵層層位、基巖厚度、松散覆蓋層厚度、工作面推進速度以及地表地形等對淺埋厚煤層開采覆巖破斷失穩(wěn)及斷裂裂縫時空演化規(guī)律的影響,得出了覆巖斷裂裂縫的動態(tài)時空演化特征、類型和分布范圍。建立了淺埋厚煤層開采覆巖導氣裂縫空氣流動力學分析模型,分析了覆巖導氣裂縫的導氣機理及導氣特征,確定了覆巖導氣裂縫的分布特征、導氣條件,得出了基于覆巖導氣裂縫等效縫寬的淺埋厚煤層開采覆巖導氣裂縫漏風流量q￠及平均漏風流速m￠的計算公式。通過現(xiàn)場實測分析和計算流體力學分析相結合,得出了覆巖導氣裂縫在工作面推進方向上的時空分布規(guī)律,建立了覆巖導氣裂縫的演化模型,為導氣裂縫影響下采空區(qū)內(nèi)漏風流場時空分布規(guī)律的分析奠定了理論基礎。建立了基于導氣裂縫控制的工作面安全生產(chǎn)保障條件,提出了保障工作面安全生產(chǎn)的技術途徑。包括減緩覆巖導氣裂縫內(nèi)漏風流速的填平封堵技術,防止采空區(qū)覆巖導氣裂縫漏風的工作面增壓通風技術,預防采空區(qū)遺煤自燃的淺埋厚煤層開采采空區(qū)注漿、注氮技術及保證工作面一定推進速度等。
[Abstract]:Aiming at the characteristics of shallow buried depth, thin bedrock and thick coal seam in the west mining area, and the overlying rock fracture through the surface during the coal seam mining, which leads to the surface air leakage, and thus causes the ventilation disorder of the working face, the CO concentration in the goaf exceeds the limit. There are some problems such as hidden danger of coal spontaneous combustion affecting production safety. Based on the geological occurrence and production conditions of Cangcao Gedan Coal Mine in Inner Mongolia, from the point of view of overburden structure movement and air flow, the field measurement, simulation of similar materials, numerical calculation and theoretical analysis are adopted in this paper. Based on the field industrial tests, the characteristics of overburden instability movement, the dynamic distribution and development of fracture fractures, the generation mechanism and space-time evolution law of overburden gas fractures under the condition of high strength mining in shallow buried thick coal seam are studied. Under the influence of gas fissures, the flow field in goaf and the characteristics of air leakage in working face are studied systematically and deeply, and the mining safety guarantee technology of shallow buried thick coal seam based on gas crack control of overburden rock is put forward. The research results have important theoretical value and practical significance for the control and safe production of strata in high strength mining of shallow thick coal seam in western mining area. Based on the mining engineering geological conditions of shallow thick coal seam in Xuancao Gedan coal mine, the temporal and spatial distribution law, dynamic development characteristics and main controlling factors of mining cracks in working face under different buried depth and overburden thickness are obtained. And the air leakage intensity, gas concentration distribution in goaf and its correlation. This paper analyzes and classifies the types of surface mining cracks and their influence on working face safety. The mechanical model of the deep beam structure of the key strata bearing overburden is established. The fracture characteristics of the first and periodic breaking of the critical layer bearing the deep beam structure, the form of instability and its influencing factors, as well as the formation mechanism of the ground fracture of the overburden through type are obtained. This paper analyzes the influence of bearing key layers, bedrock thickness, loose overburden thickness, working face advancing speed and surface topography on the time-space evolution law of overburden rock fracture instability and fracture in shallow buried thick coal seam mining. The dynamic temporal and spatial evolution characteristics, types and distribution range of overburden fracture fractures are obtained. The air flow mechanics analysis model of overburden gas fracture in shallow buried thick coal seam is established. The gas conduction mechanism and gas conduction characteristics of overburden gas fracture are analyzed, and the distribution characteristics and gas conduction condition of gas fracture in overburden rock are determined. The formula of air leakage flow Q and average air leakage velocity m of overburden gas fracture in shallow buried thick coal seam based on equivalent fracture width of overburden gas conductivity fracture is obtained. Through the combination of field measurement analysis and computational fluid dynamics analysis, the space-time distribution law of overburden gas crack in the working face is obtained, and the evolution model of overburden gas crack is established. It lays a theoretical foundation for the analysis of the spatial and temporal distribution of air leakage field in goaf under the influence of gas conduction cracks. The working face safety production guarantee condition based on the gas guide crack control is established, and the technical way to ensure the working face safety production is put forward. It includes filling and plugging technology to slow air leakage velocity in overburden gas crack, working face pressurized ventilation technology to prevent air leakage from gas crack in overburden rock in goaf, and grouting in mining goaf in shallow thick coal seam, which can prevent spontaneous combustion of coal in goaf. Nitrogen injection technology and ensure the working face certain speed of advance, etc.
【學位授予單位】：中國礦業(yè)大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：TD325;TD728
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本文編號：2212438