地下水补给
包气带
黄土
地下水位
地质学
渗透(认知心理学)
水文学(农业)
土壤科学
水流
环境科学
地下水
含水层
岩土工程
地貌学
生物
神经科学
作者
Dalei Peng,Qiang Xu,Limin Zhang,Huilin Xing,Ping Shen,Kuanyao Zhao,Xianlin Zhang
出处
期刊:Catena
[Elsevier]
日期:2021-12-07
卷期号:210: 105930-105930
被引量:4
标识
DOI:10.1016/j.catena.2021.105930
摘要
Loess slopes along the Yellow River in China are prone to failure in response to intensive irrigation. Existing studies found that the wetting front depth subjected to intensive farming water could barely reach 6 m in loess terrace. Long-term field monitoring revealed that irrigation water takes a short time to recharge the groundwater. Yet the dynamic process and mechanism of irrigation water percolation through thick unsaturated loess remains unrevealed. To address this problem, the Heifangtai terrace was selected as the study area and a series of unique full-scale controlled field irrigation experiments were carried out combined with numerical modelling. The variations in water content, pore-water pressure, and electrical resistivity over time were monitored. From the field testing, the unsaturated stratified loess layer could be divided into two vadose zones based on the water percolation characteristics, namely, transient flow zone (0–6.5 m) and steady flow zone (>6.5 m). Variation in water content presented a hysteresis effect in the transient flow zone compared with the steady flow zone. In the whole seepage process, the vertical percolation rate of 0.5 m/day was double that of the horizontal percolation rate. Furthermore, the irrigation water percolating process was modelled using a finite element code, PANDAS, which was validated by the field testing. Numerical simulation results demonstrated that the movement of wetting front was hampered by the air outflow within transient flow zone and that irrigation water reached the deep groundwater table through the thick unsaturated stratified loess within 100 days, which was consistent with the field monitoring data. This research aids in a better understanding of the irrigation water percolation process in unsaturated stratified loess in the loess region.
科研通智能强力驱动
Strongly Powered by AbleSci AI