College of Water Resources and Civil Engineering, China Agricultural University, Beijing, 100083, China.
Department of Resources and Environment, Tibet Agricultural and Animal Husbandry College, Linzhi, 860000, China.
Sci Rep. 2019 Mar 8;9(1):3954. doi: 10.1038/s41598-019-40400-4.
Erosion of freeze-thaw soil by meltwater from snow/glacier is one of the main erosion types in high altitude or latitude regions. This study aims to experimentally measure soil erosion processes over partially-unfrozen soil slopes in laboratory. The experiments including three slope gradients of 10°, 15°, and 20°, three water flow rates of 1, 2, and 4 L/min (0.06, 0.12, and 0.24 m/h), and three thawed-soil depths of 1, 2, and 5 cm were conducted to measure sediment concentration and calculate its delivery rate under seven slope lengths of 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, and 6.0 m. The sediment delivery rates from nonfrozen soil slopes under the corresponding slope gradients, flow rates, and slope lengths also were measured as control treatments. Results showed that the sediment delivery rate from both partially-unfrozen and nonfrozen soil slopes increased logarithmically with slope length. The sediment delivery rate from partially-unfrozen soil slope increased with the increased slope gradient and meltwater flow rate significantly, and the effect of water flow rate on it was greater than that of slope gradient. The thawed-soil depth did not significantly affect sediment delivery rate. The sediment delivery rate from a partially-unfrozen loamy soil slope averagely was 11.4% smaller than that from nonfrozen soil slope. This study is helpful to understand the erosion process of thawing-soil by meltwater from snow/glacier.
融雪/冰川水对冻结-解冻土壤的侵蚀是高海拔或高纬度地区的主要侵蚀类型之一。本研究旨在实验室条件下对部分冻结土壤斜坡上的土壤侵蚀过程进行实验测量。实验包括三个坡度梯度（10°、15°和 20°）、三个水流速率（1、2 和 4 L/min（0.06、0.12 和 0.24 m/h））和三个解冻土壤深度（1、2 和 5 cm），以测量泥沙浓度并计算七个坡度长度（0.5、1.0、2.0、3.0、4.0、5.0 和 6.0 m）下的输沙率。在相应的坡度梯度、水流速率和坡度长度下，非冻结土壤斜坡的输沙率也作为对照处理进行了测量。结果表明，无论是部分冻结还是非冻结土壤斜坡的输沙率都随坡度长度呈对数增加。部分冻结土壤斜坡的输沙率随坡度梯度和融雪水流速率的增加而显著增加，水流速率对其的影响大于坡度梯度。解冻土壤深度对输沙率没有显著影响。部分冻结的粉质壤土斜坡的输沙率平均比非冻结土壤斜坡低 11.4%。本研究有助于了解融雪/冰川水对解冻土壤的侵蚀过程。
