干旱矿区采动顶板导水裂隙的演化规律及保水采煤意义

随着我国煤炭资源开发重心的逐步西移,西部地区目前已成为我国煤炭的主产区。总体上,我国西部矿区降雨稀少、蒸发强烈,形成了该区极度干旱缺水、生态环境脆弱的基本特征。以新疆哈密煤田大南湖矿区为例,针对该区侏罗系含煤地层具有成岩时间晚、物理力学强度低、遇水易泥化崩解等特征,采用相似材料模拟、数值模拟等手段,结合邻矿现场实测对比,全面研究了该区顶板采动导水裂隙的发育与演化过程、发育高度与形态特征、渗透性演化规律以及在该区进行水资源保护性开采(保水采煤)的可行性。研究结果表明:研究区侏罗系含煤地层采动导水裂隙的发育裂采比一般在13.09～15.67,整体形态呈"梯台型"特征;采动影响范围内裂隙发育、演化以及渗透系数的演化均呈现"稳定增加-波动变化-恢复稳定"变化特征,导高影响范围内含水层的渗透系数明显增大,一般达到3～5倍;研究区主采煤层顶板具有"多含水结构下的高位隔水层"结构特征,具备了保水的基本水文地质前提条件;结合保护层的稳定性、III-1上段含水层的静储量、开发潜力以及在研究区进行保水采煤可行性的综合评价,探讨了在干旱矿区水资源保护性开采的重要意义。

Law of mining induced water conduction fissure in arid mining area and its significance in water-preserved coal mining

With the focus on the gradual westward shifting of coal resources development in China,the western region has become the main production areas.In general,the ecological environment is relatively weak due to the low precipitation and high evaporation.Taking the Dananhumining area in Hami coalfield,Xinjiang,as an example,in view of the late diagenesis time,low physical intensity and easily muddy disintegration of Jurassic coal-rich strata in this area,similar material simulation and numerical simulation are used.Based on the field observation and comparison of the neighboring coalmines,several significant rules are studied including the development and evolution process,the development height and morphological characteristics,the permeability evolution law in roof water flowing fractured zone and the water protection during coal mining (water-preserved mining).The results shows that in the Jurassic coal-rich strata,the development ratio of water flowing fractured fissure is generally between 13.09 and 15.67,and the overall morphology is characterized by “terrace-type”.Fracture and permeability coefficient evolution in the range of mining impacts reflect the characteristics of “stable increase-fluctuation-recovery stability”,and the permeability coefficient of aquifer increases obviously reaching 3-5 times within the influence range of the height of water flowing fractured zone.The main coal seam roof in the study area has the “high aquifuge under multi-aquifer structure” structural characteristics,which possess the basic hydro-geological preconditions for water retention.Combined with the protection seam’ stability,the upper aquifer of iii-1 static reserves,the development potential and the comprehensive evaluation of the water-preserved mining feasibility in the research area,and the significance of water protection during coal mining in arid mining area are discussed.