A study of erosion control on expressway embankment sideslopes with three-dimensional net seeding on the Qinghai-Tibet Plateau
Catena, 147, pp 463-468, 2016-12
Soil erosion on expressway sideslopes affects hillslope stability and adversely influences expressway conditions. However, few attempts have been made to quantitatively study soil erosion processes and control the effectiveness of these processes on expressway sideslopes. The objectives of this study were to investigate the effects of Elymus dahuricus cover on soil erosion processes and effectiveness. Experiments using three Elymus dahuricus cover percentages (0%, 37% and 74%) and two inflow rates (3.0 and 8.0 L min(-1)) were conducted in 3-m-long by 1-m-wide plots on expressway embankment sideslopes with three-dimensional net seeding on the Qinghai-Tibet Plateau. The results showed that when the cover percentage was increased from 0 to 37%, the mean runoff velocity decreased by 35.3-45.9%. Soil loss was also significantly lower. Compared with the soil loss from bare sideslopes, the soil loss from sideslopes with 37% cover decreased by 92.6-95.4%. Although expressway construction and maintenance are expensive and difficult in this region, at least 37% Elymus dahuricus cover on expressway embankment sideslopes with three-dimensional net seeding should be required. A soil loss equation, which was based on the cover percentage and the inflow rate, was established and evaluated for expressway embankment sideslopes in the region. The effects of the cover percentage on soil erosion were greater than those of the inflow rate. Therefore, preventing runoff-induced erosion through effective cover measures, such as three-dimensional net seeding, is critical for soil erosion control on expressway embankment sideslopes on the Qinghai Tibet Plateau of China.
Soil erosion; Expressway sideslope; Cover percentage; Three-dimensional net seeding; Qinghai-Tibet Plateau