片沙覆盖黄土区是黄土高原水蚀风蚀交错带水蚀风蚀交互作用的核心区域和黄河下游河床粗泥沙的主要源区。区域内存在明显不同于一元结构坡面的片沙在上，黄土在下的沙土二元结构坡面，可发生特殊的沙土界面潜流侵蚀，目前对这种二元结构坡面土壤侵蚀的了解甚少，这严重制约了对该区土壤侵蚀的深入研究和科学防治，进而威胁到黄河下游生态安全。本项目拟以概化的片沙覆盖黄土坡面和黄土坡面为研究对象，基于野外调查与模拟降雨试验，结合三维激光扫描技术，系统研究片沙覆盖黄土坡面沙土界面潜流侵蚀过程；揭示片沙覆盖黄土坡面沙土界面潜流侵蚀动力学机理；探寻片沙覆盖黄土坡面侵蚀形态演化过程及动力机制；确定片沙覆盖黄土坡面土壤侵蚀预报修正系数。本项目的研究将有助于对片沙覆盖黄土坡面土壤侵蚀特点的深入了解，深化对水蚀风蚀交错带土壤侵蚀特征和该区内高含沙水流形成机理的认识，为区域土壤侵蚀预报和防治提供支撑。同时也推动坡面土壤侵蚀理论的发展。

The sand-covered loess region is the heart area of the water-wind erosion crisscross region on the Loess Plateau and also is the main source of the coarser sediment in the downstream bed of Yellow River.The dual structure slope in the sand-covered loess region is different from the unitary structure slope whose soil eroison have been studied abundantly in the past. The special eroison type which is named the underflow ersion in sand-covered loess slope exist. There are few studies for this special eroison type on the dual structure slope of sand-covered loess.These have as a result to limit the intensive study for soil erosion in this region and further threat the ecological safety in the downstream bed of Yellow River.In this project, based on the sand-covered loess slope and loess slope, using the artificial rainfall and the three-dimensional laser scanner, the underflow erosion process will be systematically studied; the underflow erosion dynamic mechanism will be found; the evolution process of slope erosion micro-topography and its dynamic mechanism will be discovered; and then the corrected coefficient of predicted soil eosion on the sand-covered loess will be proposed. This project is very important to study intensively the characteristics of soil erosion in sand-covered loess region and is the basis to deeply analyze the characteristics of soil erosion and the forming mechanism of hyperconcentrated flow in water-wind erosion crisscross region. The studying results will be used to serve the soil erosion prediction and prevention in this region. In the other hand,the soil erosion on the dual structure slope will enrich the soil eroison theory on the slope.