大克泊湖床垂向渗透系数试验研究

摘要

The lakebed hydraulic conductivity is a vital parameter to study the lake/ground water interaction and is the basis for the quantitative assessment of lake water/ groundwater transformation. In this paper. the anthors present hydraulic conductivity of lakebed measured in Habor lake in the Ordos basin though size distribution determination of the lakebed sediments and in-situ permeability test to evaluated the vertical hydraulic conductivity ( Kv). The average Kv values have a variation of over four times, varying from 0. 202 to 1. 103 cm/d, indicated the Kv is heterogeneous in space. The magnitude of Kv indicates that groundwater can ' t recharge lake water directly and the major recharge is the overflow. Therefore, the groundwater can not recharge lake water in dry seasons that make the area of lake surface shrink sharply. The grain size analysis shows that the sediments are mainly clay which may originate from the weathering of the mudstone of Huanhe group.%湖床渗透系数是地下水与湖水关系研究中的重要参数之一是评价湖水与地下水定童转化关系的基础.以鄂尔多斯盆地大克泊湖为例,首先分析了湖床沉积物的颗粒组成,然后利用现场渗透试验技术进行了野外试验,计算了湖床的垂向渗透系数.计算结果表明,各测点的平均垂向渗透系数介于2.02×10-1～1.103cm/d,最大值是最小值的4倍,表明大克泊湖床的垂向渗透性能在空间具有非均质性.湖床沉积物垂向渗透系数的数量级表明,湖水很难和地下水直接发生交换,地下水主要以溢流的形式补给湖水.因此,在枯水季节,地下水无法补给湖水,导致大克泊湖的面积在蒸发作用下萎缩迅速.颗粒分析结果表明,湖床沉积物以粘土为主,根据湖区的地层岩性分析,其主要来自环河组中泥岩的风化.