低瓦斯煤矿突出源区边界地质条件的突变特征与形成机理

Coal and gas otuburst is the most deadly diaster in under coal mine worldwide,especially in China. Geologic-structural control on coal and gas outburst has long been one of the significant scientific topics. Coal and gas outbursts occurred not only in high gassy coal mines,also in low gassy coal mines over the past two dacates.Outbursts in low gassy coal mines always caused heavy loss of miner lives.Scientists and mining engineers have noticed the phenomenon for long time.However,the mechanism has not been fully understood and interpreted,and it is a new chalenge for geoscientists and mining engineers to predict and prevent this kind of mining hazard. The mechanism and geological conditions of outbursts in low gassy mines may be significantly different with ourbursts in high gassy coal mines.A recent investigation in outburst coal mines from Zhengzhou Coal Mining Gruoup revealed that geological boundary conditions of the outburst-prone area in low gassy mines changed suddenly.These geological conditions include strcutural fetures,techtonically deformed coal,recent tectonic stress field,gas content/pressure,and coalmine gas geochemistry. This research is going to develop a better uderstanding on what geologiacl boundary conditions changed in outburst-prone area in low gassy coal mines,and pursue scientific knowlledge how and why these obundary conditions changed.

瓦斯突出是世界煤矿的重大灾害，瓦斯突出的地质构造控制是国内外煤矿安全开采的重大科学和技术难题。近年来，重特大瓦斯突出事故在低瓦斯矿井接连发生，造成极为严重的人身伤亡事故。低瓦斯矿井突出的灾害性比高瓦斯矿井更为严重，其突出源区边界地质条件可能是突变的，机理研究和预测难度更大。研究两种不同类型的低瓦斯矿井突出源区边界地质条件突变特征和成因机理是揭示低瓦斯矿井突出机理的重要科学命题，对我国低瓦斯矿井突出治理，改善煤矿安全状况具有重要的理论和实践意义。项目的关键科学问题和创新之处在于探索： 1.低瓦斯煤矿突出源区地质构造-构造煤边界条件的突变特征和形成机理； 2.低瓦斯煤矿突出源区地应力边界条件的突变特征和形成机理； 3.低瓦斯煤矿突出源区瓦斯赋存边界条件的突出特征和形成机理； 4.低瓦斯煤矿突出源区瓦斯地球化学边界条件和突变特征和成因演化。

调查并研究了我国典型低瓦斯突出矿区-郑煤矿区瓦斯突出发生的瓦斯地质条件，试验分析了突出发生的特征参数f值144组和瓦斯参数40组，建立了基于能量平衡理论的低瓦斯突出发生判据的数学模型，完成了断层两盘在巷道掘进过程中地应力场变化规律及其突出危险性的模拟研究。获得了如下理论和应用成果：①构造煤赋存和地应力场状态对低瓦斯条件下突出的发生具有控制性作用，对于f值小于0.3的碎粒煤和糜棱煤，在500m、1000m埋深条件下，发生突出的临界瓦斯压力均在0.74MPa以下；对于f值小于0.2的糜棱煤，在500m、1000m埋深条件下，发生突出的临界瓦斯压力低于0.5MPa；②瓦斯突出主要发生在正断层的上盘区域，是上盘长期（形成期、发展期和煤巷掘进期间）处于地应力集中状态综合作用的结果。③本项目研究成果为河南省瓦斯突出临界值新规定（瓦斯含量6m3/t，瓦斯压力0.6MPa）奠定了理论基础，在构造煤普遍发育的豫西煤田，瓦斯突出的临界指标相应降低；为减小突出危险性，煤巷的掘进方向尽量由正断层下盘一侧向断面方向进行。