基于断层量化隐伏型煤矿基岩含水层水化学空间演化机制研究

Study on the spatial evolution mechanism of hydrochemistry in bedrock aquifer of concealed coal mine based on quantification and evaluation of fault

地质构造是控制地下水化学场形成的关键因子,但由于其类型、性质和组合方式存在较大差异,致使定量表征地质构造对含水层水化学空间演化是个难点问题,亟待解决。本文以典型隐伏型煤田——淮北煤田袁店一矿的二叠系主采煤层砂岩裂隙含水层(简称“煤系”)和石炭系太原组灰岩岩溶裂隙含水层(简称“太灰”)为研究对象,基于主成分分析和离子比例分析,阐明控制含水层水化学空间演化的关键因素,利用断层复杂系数量化地质构造对地下含水层水-岩作用的影响,揭示袁店一矿水化学空间演化机制。研究结果表明,袁店一矿煤系主要水-岩作用为阳离子交替吸附与脱硫酸,太灰主要水-岩作用为碳酸盐溶解与黄铁矿氧化。袁店一矿东部断层复杂系数平均值为0.56,中部为0.61,西部为0.71。随着断层复杂系数平均值的增加,断层愈发育,煤系在袁店一矿主要水-岩作用阳离子交替吸附与脱硫酸有向非碳酸盐溶解转变的趋势;太灰在袁店一矿主要水-岩作用碳酸盐溶解与黄铁矿氧化有进一步增强的趋势。研究成果为研究华北隐伏型煤田地下水化学演化的构造控制机制提供了新思路,奠定了良好的理论基础。

The geological structure plays a crucial role in forming the chemical composition of groundwater.However,due to the diverse types,properties,and modes of combination,understanding the spatial evolution of aquifer water chemistry in relation to geological formations remains a challenging task.In this research paper,we aim to address this issue by examining the groundwater water-rock interaction and its controlling factors in two distinct aquifers:the Permian coal measure sandstone fissure aquifer(referred to as the‘the coal measure aquifer’)and the Carboniferous limestone karst fissure aquifer(referred to as‘the Taihui aquifer’).We employ principal component analysis and ion ratio analysis to analyze these aquifers.Furthermore,we perform a quantitative evaluation of the geological structure in the Yuanyi coal mine to explore its impact on the hydrochemical characteristics of underground aquifers.Our findings show that the main water-rock interaction in the coal measure aquifer involves cation-exchange adsorption and desulfation,while in the Taihui aquifer,it primarily entails carbonate dissolution and pyrite oxidation.We also observe variations in the complexity of faults across different parts of the study area,with the eastern part having a complexity coefficient of 0.56,the central part 0.61,and the western part 0.71.With an increase in the average value of the fault complexity coefficient,the faults become more developed.As a result,the main water-rock interaction in the coal measure aquifer of the Yuanyi coal mine consists of cation-exchange adsorption and desulfation,which shows a trend towards transformation into non-carbonate leaching dissolution.Additionally,there is a further strengthening trend in the dissolution of carbonate and pyrite oxidation in the major water-rock interaction of the Taihui aquifer in the Yuanyi coal mine.These findings offer new insights and a solid theoretical foundation for studying the tectonic control mechanism underlying the chemical evolution of groundwater in concealed coalfields of North China.