| pervious asphalt pavement and bioretention facility are important sources emission reduction facilities in the process of sponge city construction.The common material for motorized driveway pervious asphalt pavement is Open-Graded Friction Courses(OGFC),since the first proposed OGFC in Germany in 1960 s,OGFC has been studied and applied for several decades.Because of OGFC's excellent performance and remarkable contribution to the city's rainwater circulation,it has been widely used in urban pavement,square and parking lot.The safety and environmental benefits with OGFC include(1)improved wet pavement frictional resistance,(2)reduced hydroplaning,(3)reduced splash and spray,(4)reduced nighttime glare,(5)improved nighttime pavement marking visibility,and(6)reduced pavement noise.The common bioretention facilities include concave green space,rainwater garden and high flower bed,which can not only reduce the total amount of rainfall runoff,but also achieve peak lag and purification of rainwater.Up to now,most of the research on combination system of pervious asphalt pavement and bioretention facility is based on monitoring data and analyzing it's hydrolodical effect.There is little further research on its mechanism of on-site infiltration and retention measures' effect.This paper first analyzes and summarizes the mechanism and calculation methods of the runoff generation and concentration of the pervious asphalt pavement and biorentention facility,and further studies the control efficiency and mechanism of the integrated system on the road rainfall runoff with the artificial rainfall experiment and the Infoworks model.The main contents and conclusions of this paper are as follows:(1)Study the mechnism of runoff generation and concentration of OGFC,put forward the calculation method applicable to the pervious asphalt pavement,and summarizes the commonly used method of calculating the concentration time,inflow and outflow of bioretention.Analyze the applicability and accuracy of the above calculation method through the actual calculation example and the SWMM model.(2)Summarizes the application satus of OGFC and the existing technical parameters,the structural design method of the pervious asphalt pavement and the bioretention facility.Designed the experimental scheme for the main factors that affect the rainfall runoff controal based on the purpose of study and experimental conditions.(3)Measured the elevation data of the experimental road and built the Infoworks model of the traditional impermeable asphalt pavement.Analyzing the control efficiency of integrated system for rainfall runoff by comparing the simulation results and monitoring data.The results show that under the condition of 1% longitudinal slope+1% cross slope,the reduction rate of peak runoff is 48.4-93.69% and the average value is 67.07%,time lag range from 15 s to 358 s and the average value is 125s;under the condition of 3% longitudinal slope+1.5% cross slope,the reduction rate of peak runoff is 40.72-86.93% and the average value is 60.03%,time lag range from 22 s to 324 s and the average value is 110s;under the condition of 5% longitudinal slope+2% cross slope,the reduction rate of peak runoff is 29.75-94.89% and the average value is 52.14%,time lag range from 11 s to 285 s and the average value is 98 s.(4)The bivariate correlation analysis of the experimental data was carried out by SPSS software,and the correlation between the main factors of the integrated system and the reduction rate of the peak runoff was obtained as follows: the peak rainfall intensity > the total rainfall volume > the pavement slope.(5)Comparing and analyzing the runoff generation and concentration process calculated by Linsley-Horton method and SCS method,and it is found that the precision is low when it is applied to the OGFC.By analyzing the experimental monitoring data,a recommended runoff coefficient corresponding to different rainfall intensities are applied to calculate runoff generation process of OGFC.(6)Calculate the contribution ratio of integrated system to the municipal pipe network inflow control.In the scenario,the contribution ratio of the pervious asphalt pavement in the integrated system to the peak reduction of the municipal pipe network inflow is 80%,the bioretention is 20%;the contribution of the pervious asphalt pavement to the peak time lag is 8%,and the bioretention is 92%.the contribution ratio of the pervious asphalt pavement in the integrated system to the total volume reduction of the municipal pipe network inflow is 76%,and the bioretention is 24%. |
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