Simulation Of Water Flow Characteristics And Research On Drainage Technology In Superelevation Transition Section Of Freeways

Ponding on the road surface is a common disease problem in superelevation transition sections.The impact of ponding on road driving safety is mainly reflected in two aspects.On the one hand,the water mist caused by ponding can reduce visibility and increase driving difficulty.On the other hand,ponding can reduce the friction between tires and the ground,which is easy to cause water skiing accidents.This article adopts a combination of theoretical analysis and numerical simulation to study the variation of water film thickness and water flow path length in the superelevation transition section with factors such as rainfall intensity,longitudinal slope,and superelevation gradient rate.A hidden continuous transverse grates device has been studied and designed to accelerate the drainage of the zero cross slope section of the superelevation transition section.The setting scheme of the grates in the superelevation transition section under different longitudinal slopes and lanes has been analyzed and calculated.The main research conclusions are as follows:(1)Through on-site research,it was found that the depth,range,and position of water in the superelevation transition section are related to the linear conditions;Summarized the causes of ponding,mainly including poor construction quality,failure of drainage system,and inevitable accumulation of water near the zero cross slope due to linear reasons.(2)Rainfall intensity has the greatest impact on water film thickness,followed by longitudinal slope,and the influence of superelevation gradient rate on water film thickness is the smallest;the longitudinal slope has the greatest impact on the longest water flow path,followed by the superelevation gradient rate,while rainfall intensity has no effect on the longest water flow path.(3)The overall trend is that the water film thickness increases with the increase of the water flow path length.To control the water film thickness,a water flow path control length with a water film thickness of no more than 4mm was calculated.It can be concluded that when the longitudinal slope is less than 1%,highways with different lanes are prone to water accumulation.(4)We have studied and designed a hidden continuous transverse grates at the zero cross slope of the superelevation transition section,and provided a layout plan for the grates under different lanes and longitudinal slopes.With a water film thickness of 4mm as the control value,when the longitudinal slope is less than 1%,only one grates needs to be set at the zero cross slope for the four lanes,while 2-4 ditches need to be set up upstream and downstream of the zero transverse slope for the six and eight lanes.Through the construction of physical engineering,it has been verified that the hidden continuous transverse grates has good drainage effect.