上方来沙对崩积体细沟形态及径流挟沙力的影响研究

崩积体细沟侵蚀是崩岗输出泥沙的重要来源。径流挟沙力是土壤侵蚀过程模型中区分土壤分离和泥沙沉积过程的核心参数。现有崩积体细沟径流挟沙力研究多采用清水冲刷非可蚀性细沟的试验方式，无法准确揭示上方来沙及其驱动下细沟形态变化特征对径流挟沙力的影响效应。本项目拟通过不同坡度、流量、坡长和上方来沙负荷条件下的放水冲刷试验，就上方来沙对崩积体细沟形态及径流挟沙力的影响展开研究。分析上方来沙作用下细沟形态变化规律，明确上方来沙在细沟形态变化过程中的作用；研究上方来沙作用下细沟侵蚀产沙特征，揭示上方来沙和细沟形态对崩积体细沟侵蚀产沙过程的影响效应，阐明上方来沙作用下细沟形态变化和侵蚀产沙过程的反馈机制；计算径流挟沙力，探究上方来沙及其驱动的细沟形态变化对径流挟沙力的影响机制，建立崩积体细沟径流挟沙力模拟公式。研究结果以期为构建崩岗区域侵蚀、泥沙迁移模型，明确崩岗水土保持综合治理的重点，提供科学依据。

Rill erosion on colluvial deposit slope is the major sediment source of Benggang. Sediment transport capacity is the key parameter to differentiate soil detachment and sediment deposition processes, and its accurate estimation is critical for improving process-based erosion models. Most recent studies regarding sediment transport capacity of rill flow on colluvial deposit slope were conducted by generating sediment-free flow on non-erodible rills, the influences of upslope sediment load and temporal changes of rill morphology on sediment transport capacity therefore are unclear. This study aims to investigate the influences of upslope sediment load on rill morphology and sediment transport capacity of colluvial deposit slope, by generating runoff under treatments of different slope gradients, rill lengths, flow rates, and upslope sediment loads. The objectives of this study are to: (1) highlight the role that upslope sediment load plays in the rill morphological evolution processes, by comparing the changes of rill morphology under clean water and upslope sediment load treatments; (2) reveal the feedback between rill morphological evolution and rill erosion processes, by studying on the responses of rill erosion to upslope sediment load and rill morphology; (3) investigate the influences of upslope sediment load and rill morphology on sediment transport capacity of colluvial deposit slope, and develop empirical relationships to estimate sediment transport capacity by incorporating the effect of upslope sediment load. The results of this study would benefit the development of erosion and sediment transport models, and the selection of erosion control practices in Benggang area.