基于组合赋权法的洛河组含水层富水性评价

Water-richness evaluation of Luohe Formation aquifer above coal seam based on combination weighting method

核桃峪井田生产能力大、煤层分布稳定,煤层顶板的厚层洛河组砂岩含水层是主要充水含水层。随着开采程度加深,导水裂隙带导通上覆含水层富水区域,发生煤层顶板水害,威胁矿井安全生产。因此,煤层顶板含水层的富水性评价是顶板水害防治的基础,查清顶板含水层富水性分布规律对煤矿的安全开采尤为重要。以核桃峪井田首采区煤层顶板洛河组含水层富水性为研究目标,基于研究区的钻孔数据等井田资料,确定了含水层厚度、岩心采取率、脆塑性岩厚度比、冲洗液消耗量、渗透系数和单位涌水量等6个影响含水层富水性的主控因素。运用基于层次分析法(AHP)和CRITIC法分别计算指标的主观权重和客观权重,运用组合赋权法求取指标综合权重,各指标综合权重分别为0.1707、0.2078、0.0976、0.1171、0.1465、0.2603;运用基于FDAHP-独立权系数法确定含水层厚度、岩芯采取率、脆塑性岩厚度比、冲洗液消耗量等4个主控因素的权重分别是0.1675、0.3120、0.2575、0.2630。引入富水性指数研究,分别提出研究区不同方法下的含水层富水性指数模型,并对煤层顶板洛河组含水层进行富水性分区与评价。结果表明:基于AHP-CRITIC法和指标较少时的FDAHP-独立权系数法的含水层富水性区域分布不均,整体变化趋势一致,具有西强东弱的特征。对于中西部地区存在大面积较强富水区,西部的强富水区以及局部强富水点位开采时需要重点防治,提前做好探放水工作。

Hetaoyu well field has large production capacity and stable distribution of coal seam,The thick sandstone aquifer of Luohe Formation in the roof of coal seam is the main water-filling aquifer which will result in coal seam roof water damage and threatening the safety of mine production with the deepening of mining degree when the water-conducting fissure zone leads to the water-rich area of the overlying aquife.It is necessary for the safety mining of coal mine to find out the law of water-rich distribution of aquifer,because water richness evaluation of coal seam roof aquifer is the basis of water hazard prevention and control.In order to evaluate the water richness of Luohe Formation aquifer in the first mining area of the Hetaoyu well field,six indexes including aquifer thickness,collecting rate of drill core,thickness ratio of brittle-plasticity,washing liquid consumption,permeability coefficient,unit water inflow were selected as evalu-ation factors by analyzing borehole data and other well field data in the study area.Combination Weighting Method is used to carry out the index weight comprehensively based on Analytic Hierarchy Process(AHP)and CRITIC method,and the comprehensive weights of each index were 0.1707,0.2078,0.0976,0.1171,0.1465 and 0.2603,respectively.Using the FDAHP-Independent weight coefficient method,the weights of the four main controlling factors,such as aquifer thickness,core extraction rate,thickness ratio of brittle plastic rock and wash fluid consumption,are 0.1675,0.312,0.2575 and 0.263,respectively.A method of aquifer water-richness evaluation index model based on the combination weighting method was proposed,and zonation of water-richness zoning was made for seam roof Luohe Forma-tion aquifer.The results show that the water richness distribution of the Luohe Formation aquifer in the roof of coal seam in the first min-ing area of Hetaoyu is uneven,which is obviously different from the distribution of each single index.The relatively weak and relatively weak water-rich areas are located in the eastern part of the study area,the middle part has medium water-rich water,and the strong water-rich areas are located in the central and western parts of the study area respectively.There are large areas of relatively strong water-rich-ness in the central and western areas.It is necessary to pay attention to the strong water-richness in the western areas and local strong wa-ter richness points and do well in water exploration and release in advance.