渭河陕西段河床渗透系数时空变化规律及其机制研究

Mechanism of spatial and temporal variability of sediments hydraulic conductivity in Weihe River : A case study in Shaan Xi

采用水头下降竖管法对2011年11月-2014年11月渭河陕西段的5个区域河床垂向渗透系数(Kv)进行计算,分析其变化规律并试图通过沉积物的物理化学性质揭示Kv值变化的机制。结果表明:1)渭河草滩段河床的Kv值大于其它4个点位;2)草滩段Kv值具有较为强的时间变异,其它4个点位Kv值在较小范围内变动即趋于稳定;3)2013年5月以后各点位的Kv值比较接近;4)河水温度差异对Kv值的时空变化有一定的影响;5)河床沉积物的类型差异是Kv值变化的主要影响因素;6)不同类型的河床沉积物对Kv值的影响机制存在差异,但Kv值均与沉积物的孔隙率(n)和不均匀系数(Cu)相关。

The values of Kvfor a streambed were derived using falling- head standpipe permeameter tests conducted at 5 study sites in the Wei He River from 2011 to 2014,and the distribution of them was analyzed. This research tried to reveal the response mechanism of the distribution by the physical and chemical properties of sediments. Conclusions are as follows： 1） the values of Kvat the site of Cao Tan was much larger than others. 2） The values of Kvat the site of Cao Tan were much more dissimilarity than other sites in temporal. 3） The Kvvalues were similar among each other site after the May 2013. 4） The water temperature could lead to some spatial and temporal variations of Kv. 5） The main factor that influences the Kvvalues was the types of sediments. 6） There was no uniform relationship for characteristics of sediments and Kvvalues to all 3 types sediments except porosity and coefficient of nonuniformity.