塔里木河河床渗透系数及其渗漏水量分析

为明晰塔里木河的水文过程,实现水资源的优化配置,采用颗粒分析法,分析塔里木河上中游河床沉积物渗透系数的时空变化特点,并借助达西定律确定了不同来水情景下4个河段的渗漏水量。结果表明:1塔里木河河床沉积物土壤颗粒的粒径0.000 5~0.5 mm,砂类土的比重为83%,因此,Sauerbrei公式用于该河流河道渗透系数的计算。2河床沉积物渗透系数与水温的变化具有一致性,段2、段4、段1和段3的年均渗透系数分别为115.3m·d~(-1)、74.5 m·d~(-1)、71.4 m·d~(-1)、45.2 m·d~(-1),呈逐渐减小趋势。3在12.5%、50%和87.5%的3个来水频率下,河段耗水量、渗漏水量及单位河长渗漏水量均呈现递减趋势;上中游总渗漏水量分别为10.85×108m3、9.94×108m3、9.13×108m3,水量渗漏集中在5—10月。4在同一来水频率下,河段渗漏水量依次为:段1段4段2段3,而单位河长渗漏水量为:段1段4段3段2。验证结果表明,渗漏水量计算结果与定量分离结果误差仅为2%,故渗漏水量及渗透系数计算结果合理。该研究可为实现塔里木河生态引水工程的合理布局和生态保护提供科学依据和技术支撑。

Hydraulic Conductivities of Riverbed Sediment and Leakage Water Volume of the Tarim River

In this paper,spatiotemporal variation of hydraulic conductivities of riverbed sediment in the upper reaches of the Tarim River was analyzed with grain-size analysis so as to clarify the hydrological process of the Tarim River and realize the optimal redistribution of water resources,and the leakage water volumes at 4 river sections under 12.5％,50％ and 87.5％ inflow frequencies were calculated with the Darcy's Law.The results are as follows:① The grain size of riverbed sediment varied in a range from 0.000 5 mm to 0.5 mm,and the percentage of sand soil in all the samples was 83.3 ％,so the Sauerbrei formula was the most suitable for calculating the hydraulic conductivities of riverbed sediment;② The change of hydraulic conductivity and water temperature was similar,the hydraulic conductivities of river section 2,section 1,section 4 and section 3 decreased gradually,and their average values were 115.3,74.5,71.4 and 45.2 m · d-1 respectively;③ Under the 12.5％,50％ and 87.5％ inflow frequencies,the wastage,water leakage and leakage per km were in a decrease trend,their total volumes were 10.85 × 108 m3,9.94 × 108 m3 and 9.13 × 108 m3 respectively in the upper reaches of the Tarim River,and the leakage occurred mainly during the period from May to October;④ Under the same inflow frequency,the water leakage was in an order of river section 1 ＞ river section 4 ＞ river section 2 ＞ river section 3,and that per km in an order of river section 1 ＞ river section 4 ＞ river section 3 ＞ river section 2.Verified results showed that the error between the calculated value of water seepage and the test result was only 2％.The calculated results of hydraulic conductivity and water leakage were reasonable and could be referred for the rational distribution of diversion works and ecological conservation in the Tarim River Basin.