再论含水层富水性评价的“富水性指数法”

Further research on “water-richness index method” for evaluation of aquifer water abundance

  • 摘要: 针对现有含水层富水性评价方法中指标权重均为固定不变的常权,忽略了单个主控因素内部之间的变化和多个因素组合状态下的变化,在“富水性指数法”思想指导下,提出了一种基于分区变权理论的富水性指数法,不仅能确定不同评价指标的权重,而且能确定同一指标处于不同状态值时的不同权重。从影响含水层富水性的岩性差异、水力特性、构造因素、地球物理参数4个方面出发,建立了能够较为全面真实刻画富水性分布规律的四大类十六小类主控因素体系;提出了主控因素指标值标准化以及无量纲化处理方法,为多因素的信息融合分析奠定了基础;应用变权理论,运用动态聚类中的K-均值聚类方法划分了主控因素各指标的变权区间阈值,研究了状态变权向量的构建及调权参数的确定方法,定量确定各主控因素对含水层富水性的相互作用关系以及相对重要性大小;构建了基于变权理论的富水性指数评价方法和数学模型。同时以彬长矿区小庄煤矿巨厚洛河组砂岩裂隙含水层为例,详细说明了基于分区变权理论的富水性指数法的具体实施步骤,利用5组抽水试验数据对评价结果进行了校正;结果表明小庄煤矿洛河组充水含水层富水性强度从西北向东南呈递减趋势,较强~强富水区主要分布在二、三盘区,一盘区西部边界也有小范围分布;中等富水区呈条带状分布于矿区中部偏西和五盘区西北部,其余地区为较弱~弱富水区。最后,将其与传统常权评价结果对比,证明变权模型更能体现含水层非均质的特性,预测精度更高。

     

    Abstract: Aiming at the problem that the index weights in the existing aquifer water-richness evaluation are all constant weights,and the changes between single main control factors and the changes under the combination of multiple factors are ignored. Under the guidance of “water-richness index method” idea,a water-richness index method based on partitioned variable weight theory is proposed,which can not only determine the different evaluation indicators weight,but also can determine different weights when the same indicator is in different state values. Based on the lithology differences,hydraulic characteristics,structural factors and geophysical parameters that affect the water richness of the aquifer,a system of main control factors of 4 categories and 16 sub-categories is established that can more fully describe the distribution law of water-richness. The method of standardization and dimensionless treatment of the index values of the main control factors are summarized,which lays a foundation for multi-factor information fusion analysis. The authors use variable weights theory and K-means clustering algorithm of dynamic clustering to divide variable weight range threshold of each index of main factors,and construct a conclusive theoretical method of state variable weight vector and adjustable weight parameters. The interaction and relative importance of each main control factor to the water-rich aquifer are determined quantitatively. The evaluation method and model of water-rich index based on variable weight theory is constructed. At the same time,taking the sandstone fissure aquifer of Xiaozhuang coal mine in Binchang mining area as an example,the specific implementation steps of water-rich index method based on zoning and variable weights are explained. Five sets of pumping test data are used to correct the evaluation results. The results show that the water-rich aquifer of the Luohe Formation water-filled aquifer in Xiaozhuang coal mine demonstrates a decreasing trend from northwest to southeast. Stronger-strong water-rich areas are mainly distributed in the second and third panels,and the western boundary of the first basin is also distributed in a small area. The middle rich water area is distributed in the west of the central part of the mining area and the northwest of five panels in a strip. The rest areas are weak to weak rich water area. Finally, compared with the traditional constant weight evaluation results,which proves that the evaluation results of variable weight can better reflect the characteristics of aquifer heterogeneity and the prediction accuracy is higher.

     

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