ISSN 1000-3665 CN 11-2202/P

    黄土塬区包气带水分运移特征研究

    Research on the characteristics of water transport in the aeration zone of loess tableland

    • 摘要: 在我国西北黄土高原的黄土塬、黄土台塬区赋存有较丰富的黄土潜水,大气降水垂直入渗是其主要补给来源,但对水分赋存和运移的空间通道认识尚有不足。文章基于董志塬、渭北黄土台塬的地貌、地层结构等水文地质条件、地下水利用动态和相关试验资料,结合黄土扫描电镜图像处理与统计分析,对黄土塬区黄土潜水和包气带水分运移的孔隙特征、过程进行了探讨并分带。研究认为孔隙是黄土地下水的主要赋存、运移的空间通道,其最小渗透等效孔径约为12 μm。由孔隙发育的马兰黄土构成的黄土包气带垂向结构组合有利于大气降水的入渗,包气带孔隙中的水分运移非常微弱缓慢,但较为连续均匀。黄土包气带可划分为气候影响带、储存调节带、缓慢运移带和毛细接收带4个带,除上部气候影响带外,其余三带处于基本稳定的水分运移动平衡状态。研究成果可为全面系统地认识黄土塬区包气带水分运移特征提供参考和借鉴。

       

      Abstract: There are abundant phreatic water in loess tablelands in the Loess Plateau of northwest China. The vertical infiltration of atmospheric precipitation is the main source of the recharge, but the spatial channels of water occurrence and migration in loess are still ambiguous. Based on the geomorphology, strata structure and other hydrogeological conditions, groundwater utilization condition and related experimental data of the Dongzhiyuan and Weibei loess tablelands, combined with scanning electron microscope image processing and statistical analysis, the pore characteristics and the migration processes of water in the loess phreatic and aeration zones are discussed and zoned. Pores are considered to be the main space channel for the occurrence and migration of loess groundwater, and the minimum equivalent pore size of seepage is about 12 μm. The vertical structural combination of the loess aeration zone composed of the Malan loess with developed pores in the upper part is conducive to the infiltration of atmospheric precipitation, and the water migration in the pores of the aeration zone is very weak and slow, but is relatively continuous and uniform. The aeration zone can be divided into four zones for loess: the climate impact zone, storage regulation zone, slow runoff zone and capillary receiving zone. Except for the upper climate impact zone, the other three zones are in a basically dynamic equilibrium state of water transport. The research results can provide important references for comprehensively and systematically understanding the characteristics of water transport in the aeration zone of loess tablelands.

       

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