Study On The Blocking Mechanism And Recovery Methods Of Permeable Bricks

As a new type of environmentally friendly porous structure material,permeable brick has good water permeability and can make the accumulated water after rain quickly seep through the pores,so it is widely used in the construction of sponge cities,which greatly eases the city after heavy rain Waterlogging problem.However,as the work cycle of the permeable brick increases,due to the erosion of rainfall and runoff,a large amount of ground sediment enters the internal pores of the permeable brick and occupies the internal space,causing it to quickly block in a short time and lose good water permeability.It brings great challenges to the daily maintenance of permeable bricks.In order to study the clogging mechanism of permeable bricks in depth,a real-time simulation system for clogging permeable bricks by rainwater runoff was developed.The ultrasonic flow profiler was used to accurately measure the surface water velocity of the permeable bricks and accurately control the rainfall runoff.Through the preliminary comparison test,ceramic permeable bricks with stable permeable properties were selected as the test materials,and the effects of particle concentration,particle grading,and rainwater runoff velocity on the blockage of permeable bricks were investigated respectively.For permeable bricks after clogging,three methods are used to clean permeable bricks: high-pressure water gun flushing,surface cleaning and backwashing.Comprehensive analysis of the recovery of permeation coefficient,particle size and percentage change of surface blocking substances,and evaluation of different cleaning methods on permeable bricks recovery effect of water permeability.The results of the study show that: when the pore clogging of the ceramic permeable brick starts,the water permeability coefficient decreases rapidly,and as the test progresses slightly,the final clogging remains stable.Among them,the concentration and particle size distribution of particulate matter in surface rainwater runoff are the main factors affecting the rapid clogging of ceramic permeable bricks,and the flow rate of surface rainwater runoff is a secondary factor affecting the rapid clogging of ceramic permeable bricks.With the increase of runoff flow velocity,the clogging process is delayed,but it cannot significantly affect the final degree of clogging.According to the clogged part,it can be divided into surface clogging and internal clogging.Compared with the three recovery methods of ceramic permeable bricks,the backwashing effect is best at 76.80%,the high-pressure water gun flushing effect is second at 46.43%,and the surface cleaning effect is the worst at 40.52%.The reason is that the backwashing is reverse water passing through the suction of the vacuum pump,which can effectively remove the blocked sand particles trapped inside and on the surface of the permeable brick,but neither the surface cleaning nor the high-pressure water gun can effectively remove the entry into the permeable brick.particle.Analyze the particle size of sand particles trapped on and inside the three groups of test bricks.In the process of controlling surface runoff pollutants,attention should be paid to particles with a particle size distribution of 20-50 μm.