Research On The Effect Of Different Permeable Pavement Base Structure On The Stormwater Runoff Quantity Control

With the rapid development of urbanization,the proportion of impermeable road surface is increasing,which leads to serious urban waterlogging phenomenon.Permeable pavement,as a typical low-impact development measure,can reduce surface runoff from the source,so it is widely used in urban construction.However,there are few researches on the combination of permeable pavement base material and base thickness.In this paper,by means of artificial rainfall infiltration test and Hydrus-1D numerical simulation,the surface runoff and rainwater infiltration rules of permeable pavement with different types of base material and different base thickness combined under different rainfall intensity are studied.The main research work and results are as follows:(1)In order to explore the surface runoff reduction effect and rainwater infiltration effect of permeable pavement of ordinary graded gravel base and reclaimed aggregate base,artificial rainfall infiltration experiment was carried out by using the rainfall infiltration device of permeable pavement developed by ourselves.The results show that the permeable pavement of reclaimed aggregate base is superior to the permeable pavement of ordinary graded gravel base in terms of increasing rainwater infiltration,reducing surface runoff and delaying the starting time of surface runoff.Therefore,recycled aggregate base permeable pavement has a broad application prospect in sponge city construction.(2)In order to explore the runoff reduction effect of permeable pavement furtherly under different rainfall intensity and different base thickness combinations,the Hydrus-1D numerical model was first used to simulate the artificial rainfall test process.The reliability of the numerical model is verified by comparing the simulated and measured displacement and calculating the Nash coefficient.The results show that the difference between measured and simulated values of permeable pavement displacement under different rainfall intensity is small,and the corresponding Nash coefficient is high,which meets the relevant requirements.It proves that the simulation results of the numerical model are reasonable.(3)The runoff law of permeable pavement under different rainfall intensity was studied by the numerical simulation of Hydrus-1D software.The study results show that the runoff regularity of reclaimed aggregate grassroots pervious pavement was similar to that of ordinary graded gravel grassroots pervious pavement under different rainfall intensity,that is,with the increase of rainfall intensity,the total surface runoff of various pervious pavement also increased,and the peak time of surface runoff occurred earlier.The results show that rainfall intensity is the key factor affecting surface runoff characteristics of permeable pavement.(4)The numerical simulation of hydrus-1D software was used to study the runoff control capacity of permeable pavement of reclaimed aggregate base and ordinary graded gravel base with different base thickness combinations.The results show that the permeable pavement with a base thickness combination of 2:3 has the strongest reduction and control ability,followed by the permeable pavement with a base thickness combination of 1:1 and the permeable pavement with a base thickness combination of 3:2 has the weakest reduction and control ability.In terms of peak occurrence delay time and surface runoff peak reduction rate,the permeable pavement with the base thickness combination of 2:3 has the best reduction effect,followed by the permeable pavement with the base thickness combination of 1:1 and the permeable pavement with the base thickness combination of 3:2 has the worst effect.It shows that permeable pavement with different base thickness has significant difference in peak occurrence delay time and surface runoff reduction effect.The above research results have important reference value for the study of surface runoff law of permeable pavement,the recovery and utilization of reclaimed materials for building demolition,and the structural form of permeable pavement base.