Experimental And Simulation Study On The Pore Clogging Mechanism Of Permeable Pavement

As a type of pervious pavement,pervious concrete can effectively reduce surface runoff because it has permeable performance.However,due to its porous performance,the permeability of permeable concrete can be seriously affected.Due to it made by no gradation of coarse aggregate,cement admixture,the permeable concrete is opaque.What’s more,the study of internal pore clogging mechanism of permeable pavement is not yet perfect.Therefore,it is necessary to study pore blockage of permeable pavement.To observe the internal movement of particles in pores and the clogging evolution directly,a test device for clogging of permeable pavement is designed and the accumulation of transparent sodium polyacrylate beads has been instead of pervious pavement aggregate.The clogging process caused by particles in surface runoff entering the internal pores of porous pavement was studied,and a visualization method was applied to analyze the clogging process in porous media.The effects of the porous pavement porosity,horizontal runoff velocity,seepage velocity,and particle size distribution on the clogging development with time,clogging development rate,and sand gradation in the clogging state were studied using the control variable method.At the same time,numerical simulation was performed using discrete element and computational fluid dynamics to study the internal movement of particles in pores and the clogging evolution.The effects of porosity,horizontal runoff velocity,seepage velocity and particle size distribution under different conditions are considered in the experiment.According to the experimental results,the evolution process of the plugging of the permeable pavement,the speed of blockage development and the distribution of the stable particle distribution of the plugging of the pervious pavement are analyzed.To study the plugging development and plugging mechanism of pervious pavement,the development and evolution process of blocking particles in a certain position of the permeable pavement are analyzed,the whole clogging process of pervious pavement in different depth of the pervious pavement is analyzed,the volume ratio of the particles in the depth direction and the speed of the clogging development are analyzed,and the percentage of blockage particles is obtained from particle coordinate information in the final steady state of blockage.The results demonstrate that the clogging process exhibits rapid clogging,partial recovery,slow clogging,and clogging stability.The most obvious change in the development process of clogging of pervious pavement concentrates on the first 2-1 Os.The factors such as porosity,the horizontal runoff,seepage velocity and sand gradation have different influence on the process of clogging development.Sand gradation plays a decisive role in clogging.And sand with different sizes has different plugging mechanism and blockage development process.The results show that the experimental results agree well with the numerical simulation.Based on the study of these scientific issues,it will provide the scientific and effective basis the prevention and restoration technology for porous pavement plugging,and the optimal design and maintenance of permeable pavement.