黄土区薄层浮土道路侵蚀试验研究

为研究降雨强度和坡度对黄土区薄层浮土覆盖的土质道路产流产沙的影响,在野外调查的基础上,通过室内模拟降雨试验研究不同雨强(1.0、1.5、2.0、2.5 mm/min)和坡度(2°、4°、8°、16°)条件下0.5 cm厚度浮土道路径流和产沙特征。结果表明:1)相同坡度条件下,平均径流率随雨强增大呈递增趋势,其变化范围在0.80~2.73 L/min,且1.5~2.5 mm/min雨强条件下平均径流率是1.0 mm/min的1.34~3.04倍,各雨强条件下浮土侵蚀阶段产流量占比范围在5.22%~40.38%;2)次降雨平均含沙量随坡度和雨强的增大均呈递增趋势,其变化范围在11.75~194.25 g/L,且与坡度和雨强分别呈显著线性和指数函数关系(P<0.05),1.0~2.5 mm/min雨强下浮土侵蚀阶段产沙量占比为0.05%~71.51%,其占比随雨强和坡度的增大存在波动,且混合侵蚀阶段产沙量与坡度和雨强呈良好的线性关系(P<0.01);3)累计产沙量随累计产流量的增大而增大且满足线性函数关系,决定系数均在0.96以上。研究结果揭示了薄层浮土道路径流侵蚀规律,可为土质道路治理及道路侵蚀模型建立提供参考。

Thin-layer regolith erosion test of soil road in loess area

The indoor artificial simulated rainfall experiment was carried out to study the characteristics of runoff and sediment yield in the loess area under different slope and rain intensity conditions.According to the field investigations,the slope of roads in this area is usually between 0°and 20°,thus we set the slope of plots to 2°,4°,8°and 16°.Four rainfall intensities were tested,from 1.0 to 2.5 mm/min with an interval of 0.5 mm/min.In our experiments,the thickness of the loose surface soil layer was set to 0.5 cm.Results showed that:1)Under the same slope condition,the average runoff rate increases with the increase of rain intensity,and the variation range was 0.80~2.73 L/min,and the value of the average runoff rate was 1.34 to 3.04 times under the rainfall intensity were 1.5 to 2.5 mm/min than that of 1.0 mm/min,and the proportion of production and discharge in the floating erosion stage under various rainfall intensity conditions ranged from 5.22%to 40.38%.2)The average sediment concentration of the sub-rainfall increased with the increasing of slope and rainfall intensity,and the range is from 11.75 g/L to 194.25 g/L,and it showed significant linear and exponential function with slope and rain intensity respectively(P<0.05).The ratio of sediment yield in floating erosion stage of 1.0~2.5 mm/min were 0.05%~71.51%,it fluctuated with the increasing of rainfall intensity and slope.There were linear relationship between sediment yield with slope and rainfall intensity in the mixed erosion stage(P<0.01).3)The cumulative sediment yield increased with the increasing of the cumulative runoff and satisfies the linear function relationship,and the coefficient of determination was above 0.96.The results revealed the path erosion law of thin layer regolith road,which could provide reference for the soil road management and road erosion model establishment.