Analytical and Experimental Study of Grooved Pavement Runoff

摘要

Drainage characteristics of grooved runways were investigated. An analytical model, developed from unsteady flow theory, was solved on a computer in order to predict runoff depths for various rainfall rates on a 100-ft-wide runway sloping transversely at 1.5%. The hydraulic roughness used by the model was predicted from pavement macrotexture. Experiments to check the validity of the model were conducted using artificial rain indoors on a 30-ft-by-15-ft portland cement concrete slab sloping at 1.5% along the 30-ft side. Rainfall rates of 1.15 and 2.45 in./hr were applied to the slab with rectangular grooves parallel to the 30-ft side and spaced at infinity, 5, 2.5, and 1.25 in. Data on the slab surface showed that water depths were smaller, and the hydraulic roughness was larger, than expected. The model was adjusted accordingly, and used to generate curves of water depths and their reductions versus distance out to 100 ft for a rainfall of 3 in./hr and a hydraulic roughness of 0.056. Predicted reductions in water depths ranged from 100% through 39 ft to 27% at 100 ft for the 1.25-in. spacing; from 100% through 19 ft to 14% at 100 ft for the 2.5-in. spacing; and from 100% through 9 ft to 7% at 100 ft for the 5-in. spacing.