| Pavement rainfall confluence is a special form of slope flow,which is the main component of urban waterlogging flow,the main power of pavement erosion and damage,and the main inducement of "vehicle water sliding" accident.Due to the shallow depth of rainfall confluence water on the road surface,large disturbance and complex flow,it is difficult to study its hydraulic parameters by theoretical calculation or field test methods.Therefore,if we can use numerical simulation to deal with the rainfall confluence problem on the road surface,it is of great significance to enrich the existing slope flow theory or solve the engineering problems such as road erosio n and urban waterlogging Righteousness.In this paper,numerical simulation method is used to study the confluence hydraulic characteristics of two kinds of asphalt pavement physical models: homogeneous and scanning.The simulation of rainfall confluence of artificial pavement takes rainfall intensity,longitudinal slope and transverse slope as variables,uses DPM to simulate rainfall,and EWF to simulate confluence,the main contents and conclusions are as follows:(1)The influence degree of the influen ce factors of the straight-line section on the rainfall confluence depth is: rain intensity > transverse slope > longitudinal slope,and the curve section is: transverse slope > rain intensity > longitudinal slope.In order to effectively reduce the rainfall confluence depth of the road surface,according to 46 groups of single factor simulation calculation results with the transverse slope as the variable,in the rainy area,the transverse slope of the straight-line section should be taken as 2% or increas ed appropriately,and the curve section should be set with superelevation of not less than 5% transverse slope.(2)The influence degree of straight line and curved line on rainfall confluence velocity is: longitudinal slope > rainfall intensity > transverse slope.In order to reduce the confluence velocity of the road and slow down the road scour,according to the 46 groups of single factor simulation results with the longitudinal slope as the variable,it is suggested that the value of the longitudinal s lope of the straight line and curve section should not be more than 4.0%.(3)The influence degree of straight section factors on rainfall convergence stability time is: rain intensity > transverse slope > longitudinal slope,and the curve section is: transverse slope > rain intensity > longitudinal slope.In order to eliminate road confluence as early as possible and slow down the hysteresis effect of road confluence,according to 46 groups of single factor simulation calculation results with transverse slope as variable,the transverse slope of transverse slope in straight section shall not be less than 2%,and the super high transverse slope of not less than 5.0% shall be set in curve section.In the simulation of scanning pavement,the velocity and depth range obtained from the simulation of artificial pavement are the boundary conditions of entrance velocity and depth,the structural depth and longitudinal slope of pavement are the control variables,the VOF model is used to track the gas-liquid interface,and the k-e model is used to calculate the fluid flow.Through the regression analysis of 60 groups of simulation experiment results,the regression calculation formulas between the stable velocity,water depth,friction coefficient and the inlet veloci ty,inlet depth,longitudinal slope and structural depth are obtained,and the influence of the inlet depth,inlet velocity,longitudinal slope and structural depth on the stable depth,velocity and friction coefficient is analyzed. |
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