The increasing number of road expansion and reconstruction leads to the road widening.It is difficult for rainwater to drain quickly from the road surface.The stagnant water causes vehicles to experience hydroplaning during braking and turning,significantly affecting driving safety.To reduce the water film thickness on super-wide pavement during rainy days and ensure driving safety,the design analysis on pavement drainage structure layout was conducted.Based on ANSYS software,the simplified road-tire-runoff model was established.The relation between hydrodynamic pressure and water film thickness was derived at vehicle speeds of 80,100,and 120 km/h.The critical water film thickness values were calculated with these 3 speeds.The influences of rainfall intensity,cross-slope gradient,pavement width,and longitudinal slope on the water film thickness were analyzed.By comparing the calculated water film thickness values with the critical values,the drainage designs were developed for the road sections with safety hazards.The drainage effects of different layout schemes were evaluated.The result indicates that for expressways with designed speed of 80 km/h,the improvement designs are necessary if the pavement water film thickness exceeds 3.92 mm;for expressways with designed speed of 100 km/h,the improvement designs are necessary if the pavement water film thickness exceeds 2.46 mm;and for expressways with designed speed of 120 km/h,the improvement designs are necessary if the pavement water film thickness exceeds 1.66 mm.The drainage structure layout scheme,setting drainage structures at lane markings,was proposed.For expressways with designed speed of 80 km/h,the cross-slope should be set at 3%;for expressways with designed speed of 100 km/h,a drainage structure should be placed at the center lane marking when exceeding ten-lane in both directions;and for expressways with designed speed of 120 km/h,a drainage structure should be installed every two lanes.
road engineeringdrainage structure layout designnumerical calculationsuper-wide pavementwater film thicknesshydrodynamic pressure
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