陕西省洛川凤栖镇离石黄土下部层位渗透性研究

PERMEABILITY OF LISHI LOESS IN FENGQI,LUOCHUAN, SHAANXI PROVINCE

通过对洛川风栖镇L_(12)～S_(15)土层8个层位16个实验点的入渗实验,研究了离石黄土下部层位的入渗特征。结果表明,洛川凤栖镇离石黄土下部层位黄土层的渗透系数较大,L_(12),L_(13),L_(14)和L_(15)这4个层位的平均值为0.90mm/分;古土壤层的渗透系数较小,S_(12),S_(13),S_(14)和S_(15)的4个层位的平均值为0.35mm/分。L_(12),L_(13)和L_(15)黄土层含水空间发育较好,利于构成含水层;S_(12),S_(13),S_(14)和S_(15)古土壤层含水空间发育弱,利于构成隔水层。上覆总厚70余米的土层重力作用没有改变洛川离石黄土下部黄土层作为含水层和红色古土壤作为隔水层的基本特性,它们的水理性质仍是受沉积时的气候条件和成壤作用的强弱控制。古土壤层也具有一定的渗透性,这是黄土地下水常常具有多层性的原因,也是造成黄土地下水分散、含水层富水量少的主要原因。离石黄土下部黄土层含水空间发育好和利于构成含水层主要是当时冷干的气候决定的,红色古土壤含水空间发育弱和利于构成隔水层主要是当时温湿的气候决定的。将洛川黄土渗水实验数据用3种入渗公式分别进行拟合得出,常用的通用经验公式和考斯加科夫公式基本适用于描述洛川凤栖镇离石黄土下部层位的入渗规律,通过计算获得的2个经验公式各参数的均值和标准差为水文和农业部门应用黄土入渗经验公式提供了重要参考值。研究还揭示,第四纪环境变化理论研究在黄土水资源开发利用方面有重要应用价值。可以根据黄土与古土壤的成壤强弱判别地下水富集规律和富集层位。成壤强、隔水性好的古土壤层和其上的成壤作用很弱、含水空间发育好的黄土层是很好的地下水含水组合,最利于地下水的富集;成壤作用弱、隔水性差的古土壤和其上厚度小、受风化成壤作用相对较强的黄土层是较差的含水组合,不利于地下水的富集。

Through the water infiltration experiment in the 8 soil layers--16 experimental points of loess and red paleosol in Fengqi of Luochuan,we studied the infiltration characteristics of Lower Lishi loess. The results show that, stable seeping rate or permeable coefficient of L12, L13, L14 and L15 loess is relatively bigger in Fengqi of Luochuan, and this four-layer average of permeable coefficient is 0.90mm/min. Stable seeping rate of S12, S13, S14 and S15 is less, and their average of permeable coefficient is 0.35mm/min. Water-bearing space of L12, L13, L14 and L15 well developed, which help form aquifer. Water-bearing space of S12, S13, S14 and S15 poorly developed, which help form water resisting layer. Gravity of overlying strata has not yet changed difference water physical properties between lower Lishi loess layers and palaeosol layers in Luochuan. Their water physical properties are still subject to weather conditions and soil formation at that time. The paleosol layers have a certain characteristic of penetrability,which is the reason that the groundwater of loess strata is multi-layering and that the groundwater is decentralized, the aquifer containing a little water. Permeable coefficient of loess was bigger,water-bearing space developed well were mainly determined by cold and dry climate at that time. Permeable coefficient of S12, S13, S14 and S15 was smaller,water- bearing space developed weakly and both of them were helpful to form water resisting layer, which were mainly determined by warm and moist climate at that time. Through separately fitting the data in the water infiltration experiment by three kinds of infiltration equation, we could prove that the common general empirical formula and Kostiakov formula basically are suitable for describing infiltration law of loess and red paleosols in Luochuan. This paper reveals that, Quaternary climate change has a controlling effect on enrichment condition and enrichment discipline of loess groundwater resources. Theoretical study of Quaternary environmental change has important application value in development of water resources in loess strata.