青藏高原不同植被措施下公路边坡产流产沙特征

Characteristics of runoff and sediment yields for highway slope under different vegetation measures in Qinghai-Tibet Plateau

为探究青藏高原公路边坡在不同植被防护措施下的侵蚀规律,提高公路边坡植被防护技术,采用野外冲刷试验研究了青藏高原公路边坡在裸坡、三维网植草、人工铺草皮等不同植被防护措施下的产流产沙特征,分析了不同措施下的防护效率与拦沙机理。试验结果表明:3、8L·min^(-1)冲刷流量下的平均初始产流时间分别为225.50、163.27s,初始产流时间与流量和植被盖度之间具有显著相关性;8L·min^(-1)冲刷流量下的产流稳定时间较3L·min^(-1)提前了约2min;植被措施的拦沙效应主要体现在对粗颗粒泥沙的拦蓄上,边坡产流量和产沙量随植被盖度的增加而减小;植被措施拦截径流效率和拦截泥沙效率的平均值分别为55.7%、53.5%;综合防护效果从大到小依次为74%盖度三维网植草、37%盖度三维网植草、中部铺草皮、上部铺草皮、裸坡,建议采用以草皮为骨架配以三维网植草的边坡植被综合恢复技术。

In order to explore the erosion law on highway slope with vegetation protection measures and improve highway slope vegetation protection technology in Qinghai-Tibet Plateau, field scouring tests were carried out to study the characteristics of runoff and sediment yields on highway slope in Qinghai-Tibet Plateau under different vegetation protection measures including bare slope, three dimensional network seeding and artificial turfing, and the protection efficiency and sediment interception mechanism under different measures were analyzed. Test result shows that when the scouring flow rates are 3 and 8 L·min^-1 in Qinghai-Tibet Plateau, the average initial producing times are 225.50 and 163.27 s respectively. There is significant correlation among the initial runoff producing time, the flow rate and the vegetation coverage. The runoff producing stably time under scouring flow rate of 8 L·min^-1 advances by about 2 min compared to the scouring flow rate of 3 L ·min^-1. The sediment interception effect of vegetation measures mainly embodies in interception of sediment with coarse particles. The slope runoff and sediment yields decrease with the increase of vegetation coverage. The average runoff and sediment interception efficiencies of vegetation measures are 55. 7% and 53.5% respectively. The orders of comprehensive protection effects from big to small are three dimensional network seeding with 74% coverage, three dimensional network seeding with 37% coverage, artificial turfing in the middle, artificial turfing at the top, and bare slope. The comprehensive recovery technology of slope vegetation combining turf as frame and three dimensional network seeding is suggested. 4 tabs, 5 figs, 34 refs.