煤炭高强度重复采动下地下水资源漏失规律研究

Study on law of groundwater resources leakage under high intensity repeated mining

我国煤炭资源开发重心西移,但西部地区生态环境脆弱,地下水资源宝贵,煤炭高强度开采与地下水及生态环境保护矛盾日益加剧。近年来,西部多数矿区逐渐开拓开采下组煤层,针对多层煤层重复采动对地下水资源影响规律研究不足等问题,以神东矿区布尔台煤矿42202工作面为研究对象,采用现场实测以及数值模拟手段,对该区煤层重复采动顶板导水裂隙带的发育高度进行了实测与计算,结果表明:42煤开采后导水裂隙带最大发育高度达到顶板以上160 m,沟通了延安组和直罗组含水层,但未沟通白垩系志丹群含水层;基于导水裂隙带监测结果,采用FEFLOW数值模拟方法预计了42202工作面采后涌水量为63 m^(3)/h,与实际涌水量55 m^(3)/h接近,进一步表明工作面涌水主要来自延安组与直罗组含水层;42202工作面采后延安组含水层水位下降幅度达到57.3 m,直罗组含水层水位下降11.9 m,白垩系志丹群含水层水位基本维持稳定,由此可知,煤层采后对延安组含水层扰动程度最大,对直罗组含水层扰动程度次之,而并没有对白垩系志丹群含水层造成影响;煤层采动导水裂隙是地下水资源漏失的主要通道,其发育高度及规模决定了煤炭开采对含水层的扰动程度,抑制煤层开采后顶板导水裂隙带发育是实现西部大型矿区保水采煤的关键点,尤其是随着西部煤炭资源的深部开发,多层煤层开采后覆岩破断规律及其多场耦合特征、导水裂隙的演化规律是今后重要的研究方向。研究成果完善了多煤层开采保水理论,为实现我国西部煤炭资源的绿色开发提供支撑。

The focus of coal resources development in China has shifted to the west, but the ecological environment in the western region is fragile and groundwater resources are precious. The contradiction between high-intensity coal mining and groundwater and ecological environment protection has become increasingly serious. In recent years, most mining areas in the west have gradually developed and mined the lower coal seams. In view of the lack of research on the influence of repeated mining in multi-layer coal seams on groundwater resources and other issues, field measurement and numerical simulation have been used to measure and calculate the development height of water flowing fractured zone by taking the No.42202 working face of Bultai Coal Mine in Shendong Coal Mine Area as the research object. The results show that the maximum development height of the water conducting fracture zone after the mining of the 42 nd coal seam reaches 160 m above the roof, which connects the aquifer of Yan’an formation and Zhiluo formation, but does not connect the aquifer of Cretaceous Zhidan group;based on the monitoring results of the water conducting fracture zone, the water inflow of No.42202 working face is estimated to be 63 m^(3)/h by FEFLOW numerical simulation method, which is close to the actual water inflow(55 m^(3)/h), further showing that the water inflow of working face mainly comes from the aquifer of Yan’an formation and Zhiluo formation;after the mining of No.42202 working face, the water level of Yan’an formation aquifer decreased by 57.3 m, and Zhiluo formation aquifer decreased by 11.9 m, and the water level of Cretaceous Zhidan group aquifer basically remained stable. It can be seen that the coal seam has the greatest disturbance to the Yan’an formation aquifer, followed by Zhiluo formation aquifer, and has no effect on Cretaceous Zhidan group aquifer;The water flowing fractured zone of coal seam mining is the main channel of groundwater resources leakage, and its development height determines the degree of disturbance of coal mining on aquifers. Restraining the development of roof water conducting fractured zone after coal mining is the key point to realize water conservation coal mining in large western mining area, especially with the deep development of coal and rock resources in the west, the overburden fracture law and its multi field coupling characteristics after multi-layer coal seam mining. It is an important research direction in the future to study the evolution law of water diversion fracture zone. The research results improve the water conservation theory of multi seam mining, and provide a support for the green development of coal resources in western China.