干旱区外排土场表土毛细试验研究

Capillary test of topsoil in external dump of arid area

为了提高干旱区外排土场灌溉水的利用效率,通过重构包气带毛细层,来改善土壤毛细作用程度,使储存在表土下部浅层的水分得以通过毛细作用及时提供给植物根部,并且利用试验获得毛细水上升高度与上升时间的规律来确定合理的灌溉频率,以红沙泉露天煤矿外排土场表土为例,通过室内物理实验,探究并获得土壤毛细作用湿润锋最大上升高度,上升速率及其他参数。通过软件建模分析出土壤水力特征曲线,并计算出毛细最大上升高度。研究结果显示:土壤毛细作用发生初期,湿润锋向上移动速度较快,2h内快速降至较低速度,在第17d毛细水上升至最大高度73.6cm,为重构干旱区外排土场表层及植被修复提供基础参考。

In order to improve the utilization efficiency of irrigation water in waste dump in arid area,it is proposed to improve the soil capillarity by reconstructing the capillary layer of the vadose zone,so that the water stored in the shallow layer of the bottom of the topsoil can provide the plant roots in time through capillarity.Meanwhile,the reasonable irrigation frequency was determined by the law of rising height and rising time of capillary water obtained from experiments.Taking the topsoil of the external dump of Hongshaquan open-pit coal mine as an example,the maximum rising height,rising rate and other parameters of soil capillary wetting front are explored and obtained through indoor physical experiments.The soil hydraulic characteristic curve is analyzed by software modeling,and the maximum capillary rising height is calculated.The results show that at the initial stage of soil capillarity,the wetting front moves upward rapidly,and then drops to a lower speed within 2 h,and the capillary water rise to the maximum height of 73.6 cm on the 17 th day.