针对生产建设过程中工程开挖引发严重的水土流失问题,通过野外模拟降雨试验,研究了不同开挖坡度(30°,40°,50°)坡面产流、产沙特征。结果表明:坡度、雨强均能对开挖面产流、产沙过程造成重大影响,随着坡度增大,不同雨强(0.65,1.15,1.65 mm/min)下开挖面产流、产沙参数值增大,产流率介于0.47～0.72 mm/min之间,径流系数介于0.39～0.63之间;产沙率介于8.64～49.80 g/(m²·min)之间,径流含沙量介于17.27～77.64 kg/m³之间;但在相同坡度下,随着降雨强度的增大,产流、产沙参数值的变化存在差异。产流率随雨强增大而增大,径流系数的中(1.15 mm/min)、高(1.65 mm/min)雨强无明显差异。坡度30°的开挖面产沙率随雨强的增大而增大,坡度增大时,中、高雨强坡面产沙率接近;50°开挖面产沙率和径流含沙量在3个雨强下呈高—低—高势。试验成果为开挖面水土流失的预测、评价提供数据支撑,同时也为生产建设项目水土流失防治及水土保持监督执法提供科学依据。

Engineering excavated slope is the key source of soil and water loss in project construction. In this research, field simulated rainfall experiments were conducted to study the effects of slope gradient (30°, 40°, 50°) and rainfall intensity (0.65, 1.15, and 1.65 mm/min) on runoff and sediment yield characteristics of excavated slope. Results showed that both slope gradient and rainfall intensity have significant effect on runoff and sediment yield. As slope gradient increases, runoff and sediment parameter values increase in the presence of different rainfall intensities, with runoff rate being 0.47-0.72 mm/min, runoff coefficient 0.39-0.63, sediment rate 8.64-49.80 g/(m²·min), and sediment concentration 17.27-77.64 kg/m³. But in the presence of the same slope gradient, runoff rate increases with rainfall intensity increasing, and runoff coefficient has no obvious difference for medium (1.15 mm/min) and high (1.65 mm/min) rainfall intensity. For excavated slope of 30° gradient, the sediment rate increases with rainfall intensity increasing; while the sediment rate under medium and high rainfall intensities is very close when the slope gradient increases. For excavated slope of 50° gradient, the sediment rate and sediment concentration are high, low, and high respectively under the three rainfall intensities.