水蚀风蚀交错区不同坡长坡面产流产沙过程

A Field Experiment of Runoff and Sediment Yielding Processes of Different Slopes in Water and Wind Erosion Crisscross Region

通过野外径流冲刷模拟试验,研究了水蚀风蚀交错区不同坡长坡面产流产沙过程。结果表明:1坡面径流起始时间、止流时间随着坡长的增加而增加,起流阶段坡长每增加一倍,起流时间不呈比例增加,但止流阶段坡长每延长一倍,止流时间呈比例增加;2在整个冲刷过程中,4、8、16 m坡长的平均流速分别为0.165、0.170、0.177 m/s,随着坡长的增加,平均流速略有增大,瞬时流速最大值发生在8 m坡长的坡面,4、8 m坡长的坡面径流流速总体上随着冲刷历时波动幅度比16 m坡长的剧烈;34、8、16 m坡长的平均侵蚀速率分别为54.15、75.32、23.02 g/(m2·min),随着坡长的增加,侵蚀速率呈先增大后减小的变化趋势,冲刷过程中4 m和8 m坡长的侵蚀速率陡涨陡落,16 m坡长的变化相对平缓;4坡面产流3 min之内,不同坡长坡面径流的含沙量均出现峰值,进而出现不同程度的下降,而且随着坡长增加,含沙量呈现先增大再减小的变化趋势。

The runoff and sediment yields processes of different slope lengths in water and wind erosion crisscross region were investigated by a simulated field scouring experiment. The length of the experiment was 4 m, 8 m and 16 m respectively. The results show that a) with the increasing of the scouring time the runoff generation time and stopping time increase. At runoff generation stage, when the slope length doubles, the generation time does not increase proportionately. But at the runoff generation stage, when the slope length doubles, the runoff stopping time increases proportionately. With increasing of slope the runoff velocity increases firstly, then gradually to relative stable;b) the average runoff velocity of 4m, 8m and 16m long slopes is 0. 165 m/s, 0. 170 m/s and 0. 177 m/s respectively. Namely, with increasing of slope length, the average runoff velocity increases slightly. The different slope lengths instantaneous velocity maximum occur at 8m slope. During the scouring process, the runoff velocity of 4m and 8m fluctuates more intensely than that of the 16m slope. The erosion rate of different slopes increases first and then decreases with scouring duration increase; c) the average erosion rates of 4m, 8m and 16m long slopes are 54.15, 75.32 and 23.02 g/( m2 min) respectively. With the increase of slope length, the erosion rate increases at first and then decreases. In terms of the scouring process, the erosion rate curves of 4m and 8m slopes are steep rising and falling sharply but the change of 16m slope is relative gentle and; d ) within 3 minutes, the sediment concentration of runoff of different slopes shows a peak. Then the sediment concentration decreases with various degrees. With the increase of slope length, the sediment concentration shows firstly increasing and then decreasing.