坡面侵蚀水沙流时间变化特征的模拟实验

Simulating Experiments of Temporal Change Characteristics of Runoff and Sediment on Slope

多坡段实验模型以黄土丘陵沟壑区垂向上梁峁坡面与沟谷坡面构成的坡沟系统为原型,采用人工降雨模拟实验方法,对坡沟系统土壤侵蚀链内降雨径流产沙随时间变化的规律进行了系统的研究。结果表明:雨强29 7mm/h时36′40″开始产流,60 5mm/h时3′43″产流,90 2mm/h时2′30″产流。雨强29 7mm/h时侵蚀过程以面蚀为主,产沙起伏20min出现一次。60 5mm/h时以面蚀与细沟蚀为主,35°陡坡伴有崩塌、滑塌等重力侵蚀,产沙波动平均12min出现一次。雨强90 2mm/h时坡面上细沟发育充分,有细沟合并及出现浅沟侵蚀现象,35°坡崩塌、滑塌剧烈,产沙过程波动频繁,每10min一次。雨强29 7mm/h时单位流量的产沙量为0 10kg/L;雨强60 5mm/h时为0 30kg/L;雨强90 2mm/h时为0 41kg/L。流量的大小影响了侵蚀方式和形态分异的程度,使产沙过程出现强弱相间的波动性特点。

Based on the prototype of the vertical belts difference from hillslope to gully slope in the slope-gully system in loess region, the temporal change of runoff and sediment in the soil erosion chain of the slope-gully system was studied by simulating rainfall on block diagram combined to multi-slope sections The results showed that the runoff time varied with rainfall intensity Corresponding with rainfall intensity of 29 7mm(hr)^-1,60 5 mm(hr)^-1,90 2 mm(hr)^-1, the runoff time is 36′40″,3′43″,2′30″ respectively When the rainfall intensity was 29 7mm(hr)^-1, erosion process was mainly of sheet erosion, and the runoff and sediment occurred again in 20min intervals When the rainfall intensity was 60 5 mm(hr)^-1, sheet and rill erosion were main, and the gravity erosion such as falling landslip and creep occurred on the steep slope of 35°, the process of runoff and sediment occurred again at the average of 12min intervals rill developed well on hillslope and shallow gully occurred with the rainfall intensity of 90 2 mm(hr)^-1, on the slope of 35°, falling landslip and creep were intensive, and the time interval of process of runoff and sediment is10min When the rainfall intensity was 29 7mm(hr)^-1, 60 5 mm(hr)^-1, 90 2 mm(hr)^-1, the sediment yields per runoff was 0 10kg/l, 0 30kg/l and 0 41 kg/l respectively The runoff not only influenced erosion patters and their difference degree, but also leaded to fluctuant characteristics alternating with strong and weak of the process of runoff and sediment 