山前洪积扇坡面细沟侵蚀跌坑特征的试验研究

跌坑的出现是坡面侵蚀过程中的重要现象，标志着细沟侵蚀正在发育，跌坑的贯穿标志着细沟的形成。采用土槽冲刷模型试验，选取流量、坡度、冲刷时间和坡面形态作为影响跌坑发育的因子结合正交试验调查了不同试验条件下跌坑发育特征及影响因素。结果表明：影响跌坑发育的因素主次为冲刷时间、流量、坡面形态、坡度；跌坑沿坡面连续分布，深度具有波动性，沿坡向下呈现先增大后减小的趋势，最大值一般发育在坡面中部；根据跌坑的发育特征将坡面细沟侵蚀划分为片蚀、细沟雏形、细沟发育和细沟调整四个阶段；坡面细沟侵蚀跌坑深宽积与土壤侵蚀量具有较显著线性关系。研究结果对输油管线水毁及水土流失防治具有一定的参考价值。

Experimental study of drop pit characteristics of rill erosion on foreland pluvial fan slopeland

The appearance of drop pit is an important phenomenon in the process of slope erosion, which indicates that the rill erosion is developing gradually; the rill formation is marked by the connectivity of the drop pit. The development characteristics and distribution of the pit were investigated by the soil flume flushing model test with orthogonal design of flow, slope gradient, scouring time and slope morphology. From primary to secondary, the order of the factors influencing the development of drop pit ranked as: scouring time, flow, slope morphology, and slope gradient. The drop pit was continuously distributed along the slope and the its depth was volatility. The trend of the pit depth firstly increased and then decreased with the downward trend of slope, and its maximum value was generally in the middle of the slope. According to the characteristics of the development of the pit, the rill erosion of the slope was divided into four stages: sheet erosion, rill prototype, rill development and rill adjustment. There was a significant linear relationship between the product of depth and width of the rill erosion and the soil erosion amount. This result had a certain reference value for researching oil vapor pipeline flood damage and controlling water soil erosion.