Abstract:Relying on a certain expanded two-way eight-lane expressway in the southwest region, and based on the parameters such as the mainline design, climatic conditions and traffic operation status, the water film thickness of different lanes is calculated through multi-element theoretical formulas, and the water film thickness and aquaplaning risk of multi-lane expressways under heavy rainfall conditions are analyzed. The research results show that the water film thickness of the outer lanes is significantly higher than that of the inner lanes due to the longer drainage path and smaller synthetic slope. When the rainfall intensity is 178 mm/h, the water film thickness of the outermost lane reaches 2.494 mm about three times that of the inner lane, far exceeding the critical value of 1.2 mm for aquaplaning. When the rainfall intensity is 60 mm/h, the water film thickness of the permeable asphalt pavement is 36% lower than that of the ordinary pavement, and the increase is suppressed by 20%~30%. Based on the mapping relationship between water film thickness and aquaplaning speed, a lane-specific speed limit strategy is proposed, that is when the rainfall intensity is 60 ~150 mm/h, the speed limit for the outer lanes is 60~80 km/h, and for the inner lanes, it is 90~110 km/h, and in extreme rainfall conditions, the speed limit for the entire area is reduced to 60~80 km/h. Combined with permeable pavement, the risk of aquaplaning can be further reduced, providing a basis for drainage optimization, traffic control and safe operation of multi-lane expressways in rainy days.
