College of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China.
China Academy of Transportation Science, Beijing 100013, China.
Int J Environ Res Public Health. 2023 Mar 10;20(6):4907. doi: 10.3390/ijerph20064907.
A variety of slope water and soil conservation measures have been taken along the Qinghai-Tibet Highway, but the systematic comparison of their erosion control ability needs to be strengthened, especially in the permafrost area. To explore the applicability of different measures to control runoff and sediment yield, field scouring experiments were conducted for different ecologically protected slopes, including turfing (strip, block, full), slope covering (gravel, coconut fiber blanket), and comprehensive measures (three-dimensional net seeding). Compared with the bare slope, the bulk density of the plots with the ecological protection measure decreased, the moisture-holding capacity and the organic matter increased correspondingly, and the average runoff velocity also decreased. The soil loss and runoff had a similar trend of different ecological protection measures. The relationship between the cumulative runoff and sediment yield of different measures exhibited a power function, with the increase of scouring flow and the runoff reduction benefit and sediment reduction benefit in different ecological protection-measured plots showing a decreasing trend. The average runoff reduction benefit decreased from 37.06% to 6.34%, and the average sediment reduction benefit decreased from 43.04% to 10.86%. The comprehensive protection measures had the greatest protection efficiency, followed by turfing, while the cover measure had limited improvement. Soil characteristics, vegetation coverage, and the scouring inflow rate are key factors that influence protection efficiency. The results suggest that comprehensive measures and turfing be taken rather than cover measures or bare slopes. This work provides an experimental reference for ecological protection methods for highway slopes in the permafrost area.
已沿青藏公路采取了多种坡面水土保持措施，但仍需加强对其侵蚀控制能力的系统比较，尤其是在多年冻土区。为了探索不同措施对控制径流量和泥沙产量的适用性，对不同生态保护坡面（植草带、植草块、植草满铺、坡面覆盖、砾石覆盖、椰丝纤维毯覆盖和综合措施）进行了野外冲刷试验。与裸坡相比，生态保护措施下的样地容重降低，持水能力和有机质含量相应增加，平均径流流速也降低。土壤流失和径流量的变化趋势与不同生态保护措施相似。不同措施的累积径流量和泥沙产量呈幂函数关系，随着冲刷流量的增加，不同生态保护措施样地的减流效益和减沙效益呈下降趋势。平均减流效益从 37.06%下降到 6.34%，平均减沙效益从 43.04%下降到 10.86%。综合保护措施的保护效率最大，植草次之，而覆盖措施的效果有限。土壤特性、植被覆盖度和冲刷入流率是影响保护效率的关键因素。结果表明，应采取综合措施和植草措施，而不是覆盖措施或裸坡。这项工作为多年冻土区公路边坡的生态保护方法提供了实验参考。
