摘要
河床垂向渗透系数是研究河流与地下水转化关系和转化强度的重要水文地质参数。选取柴达木盆地巴音河为研究对象,采用水头下降竖管试验法测定了巴音河下游细土平原带38组河床垂向渗透系数,利用传统统计学方法检验分析了其分布规律和空间变异性。结果表明,河床沉积物垂向渗透系数(Kv)在1. 77~15. 56 m/d之间变化,总体呈现正态分布,且沿流程逐渐变小。河中心沉积物的Kv值明显大于河两岸,但其变异系数小于两岸。沉积物的颗粒大小与分布是导致河床沉积物垂向渗透系数变异的关键因素,河流形态与交互带水文过程对河床沉积物Kv的影响也不容忽视。
The vertical hydraulic conductivity of riverbed sediment is an important hydrogeological parameter,influencing the exchange with groundwater in river basin. This paper selects the Bayin river in Qaidam basin as the research object and 38 groups of vertical hydraulic conductivity are obtained by using falling-head permeameter test in the downriver fine soil plain. The distribution and spatial variability are analyzed by using traditional statistical methods. The results show that the vertical hydraulic conductivity( Kv) of riverbed sediments varies within the range of 1. 77 ~ 15. 56 m/d and obeys normal distribution with gradually decreased along the flow. The value of Kvin the middle of the river is obviously greater than that on riverside,but the coefficient of variation is smaller than that on bank of the river. Size and distribution of sediment particles are the key factors leading to the variation of Kv,while the river morphology and interaction of hydrological processes also cannot be ignored.
引文
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