School of Environmental Studies, China University of Geosciences, Wuhan 430074, China.
Ningxia Institute of Land and Resources and Monitoring, Yinchuan 750002, China.
Int J Environ Res Public Health. 2021 May 12;18(10):5098. doi: 10.3390/ijerph18105098.
To study the lateral seepage field in the tension saturated zone (TSZ), an experiment with no evaporation and precipitation infiltration was carried out in a self-made seepage tank filled up with fine sand. Based on the data and plots obtained, the lateral seepage field distribution features in the TSZ can be divided into three area for discussion: ascending area, descending area, and the nearly horizontal flow area. In the ascending and descending area, the total water potential gradient diminished from the recharge area to the discharge area and the seepage velocity was faster. In the nearly horizontal flow area, the total water potential gradient was lower and the seepage velocity was slower. The pressure potential gradually decreased horizontally from the recharge area to the discharge area, while in the vertical profile, it gradually decreased from the bottom to the top in the whole seepage area. In the absence of evaporation, the vertical water exchange among the saturated zone, TSZ, and unsaturated zone in nearly horizontal flow area is weak. Contrarily, in the ascending area and descending area, vertical water flows through both the phreatic surface and the upper interface of the TSZ. When there is lateral seepage in the TSZ, the thickness of the TSZ generally increases from the ascending area to the nearly horizontal area and then to the descending area. It should be pointed out that in the nearly horizontal area, the TSZ thickness is approximately equal to the height of the water column. Overall, the lateral seepage in the TSZ can be regarded as a stable siphon process, hence the siphon tube model can be further used to depict this lateral seepage.
为了研究张紧饱和带（TSZ）中的侧向渗流场，在一个自制的渗流箱中进行了无蒸发和降水入渗的实验，渗流箱中装满了细砂。根据获得的数据和图表，TSZ 中的侧向渗流场分布特征可分为三个区域进行讨论：上升区、下降区和近乎水平流动区。在上升区和下降区，总水势梯度从补给区向排泄区减小，渗流速度较快。在近乎水平流动区，总水势梯度较低，渗流速度较慢。压力势从补给区到排泄区逐渐减小，而在垂直剖面中，整个渗流区从底部到顶部逐渐减小。在没有蒸发的情况下，近乎水平流动区饱和带、TSZ 和非饱和带之间的垂直水交换较弱。相反，在上升区和下降区，垂直水流穿过潜水面和 TSZ 的上界面。当 TSZ 中有侧向渗流时，TSZ 的厚度通常从上升区向近乎水平区再到下降区逐渐增加。需要指出的是，在近乎水平区，TSZ 的厚度近似等于水柱的高度。总体而言，TSZ 中的侧向渗流可以看作是一个稳定的虹吸过程，因此可以进一步使用虹吸管模型来描述这种侧向渗流。
