藏东南高寒土坡面细沟水流输沙能力变化特征

为探究高寒土坡面细沟侵蚀过程机理，建立科学的坡面细沟输沙能力因子模型，服务高寒坡面水土流失治理工作，以藏东南高寒土壤为研究对象，采用室内径流放水冲刷试验，探讨不同流量和坡度条件下细沟水流输沙能力特征。结果表明：（1）高寒土坡面细沟水流输沙能力的临界坡长随输沙能力的增加而变短，范围为3.27~8.31 m；坡度在15°~25°时，临界坡长大约稳定在5.0 m；（2）不同坡度下，高寒土细沟水流输沙能力与流量表现为明显的线性正相关关系（T_c=Aq）；小坡度的输沙能力受流量的影响程度大于大坡度；（3）高寒土细沟水流输沙能力与坡度可以用指数方程较好地表示（T_c=-ae^（-S/b）+c），输沙能力随坡度的增大先快速增大，后逐渐过渡到平稳，当坡度达到15°时增幅平缓；（4）坡面细沟水流输沙能力可以用二元幂函数方程T_c=1697.83S^0.491q^1.043表示。通过本模型与其他模型的比较分析，ANSWERS模型在计算高寒土的坡面细沟水流输沙能力还值得商榷，本试验模型、Lei模型与Gao模型均能较好地模拟高寒区细沟侵蚀输沙能力。

Variation Characteristics of Sediment Transport Capacity of Rill Flow in Alpine Soil in Southeast Tibet

In order to explore the mechanism of rill erosion process on alpine soil slope in Southeast Tibet, establish the factor model of sediment transport capacity, and provide scientific basis for controlling soil and water loss on slope surface, this paper took the alpine soil in the Tibet Plateau as the research object, and carried out an indoor runoff scouring experiment. The results showed that: (1) The critical slope length of sediment transport capacity decreased with the increase of sediment transport capacity, ranging from 3.27 m to 8.31 m. When the slope was 15°~25°, the critical slope length was about 5.0 m. (2) Under different slopes, the sediment transport capacity increased with the increase of discharge, which could be well described by a linear equation (T_c=Aq). The influence of the same discharge on small slope was greater than that on large slope. (3) The sediment transport capacity and slope could be well expressed by an exponential equation (T_c=-ae^(-S/b)+c). With the increase of slope, the sediment transport capacity increased rapidly at first, and then gradually leveled off, and increased gently when the slope reached 15°. (4) The sediment transport capacity could be expressed by a two-dimensional power function equation T_c=1697.83S^0.491q^1.043. Compared with other models, ANSWERS model was not suitable for calculating sediment transport capacity of Alpine soil, but the performance of Zhang model, Gao model and Lei model were as good as this model.