Abstract:

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.

Key words: excavated slope, soil and water loss, runoff and sediment yield, rainfall intensity, simulated rainfall, construction project