管道孔径对西南喀斯特坡地水土漏失的影响

基于西南喀斯特坡地近地表岩溶管道的调查统计,建立喀斯特区地表—地下二元空间水土过程试验微区,通过人工模拟降雨试验,研究不同雨强下(52,133 mm/h)岩溶管道孔径大小(1,2,5 cm)对水土地下漏失过程的影响.结果表明:(1)岩溶管道孔径的增大显著增大了地下径流系数和径流强度,但对初始产流时间的影响并不显著;在中...

Impact of Conduit Aperture on Soil and Water Loss on Karst Slope in Southwest China

Based on the investigation and statistics of karst slope near-surface karst conduits, this paper established a test micro-area of surface-underground binary space water and soil process in Karst area. Through artificial simulated rainfall test, the influence of pore size (1 cm, 2 cm, 5 cm) of karst conduits on water and soil leakage process under different rainfall intensities (52 mm/h and 133 mm/h) was studied. The results showed that:(1) The coefficient of underground runoff and the intensity of runoff increased significantly with the increases of pore size of karst conduits, but the effect on the initial runoff time was not significant. Under the moderate rain intensity (52 mm/h), the time required for initial runoff generation increased with the increases of pore size. However, under heavy rain (133 mm/h), the initial runoff time decreased with the increases of pore size. (2) With the increases of pore size, the characteristic curve of runoff intensity under moderate rain intensity (52 mm/h) showed that it increased first and then tended to be stable. The runoff intensity at mid-slope position was proportional to the pore size, and the upstream and downhill positions were not significantly affected by the pore size. The change order of runoff intensity with the pore size was 5 cm>1 cm>2 cm. The runoff intensity under heavy rain (133 mm/h) showed a continuous upward trend with the increases of pore size, and the gross runoff intensity at 2 cm and 5 cm aperture increased by 75% and 74% respectively compared with that at 1 cm. (3) Underground sediment yield of different karst conduits was proportional to their pore size. Under medium rain intensity (52 mm/h), the sediment yield of 2 cm and 5 cm karst conduits with pore diameter was 2.5 and 14.9 times of that of 1 cm respectively. Under heavy rain (133 mm/h), the sediment yield of 2 cm and 5 cm karst conduit with pore diameter was 6.9 and 10.3 times of that of 1 cm respectively. (4) Under heavy rain (133 mm/h), the order of mass loss of sediment in different particle size ranges was:particle size less than 2 mm>3~2 mm>5~3 mm>5 mm or more. These research results are helpful to further understand the influence of karst pore size on underground leakage in southwest karst area and provide reference for water and soil erosion prevention in this area.