Research On Application Technology Of Permeable Asphalt Pavement In Sponge City Construction

With the increasing degree of urbanization,the original natural soil of the city was quickly replaced by steel-concrete buildings or non-permeable hardened ground,resulting in a rapid increase in the proportion of impervious areas,which in turn changed the permeability of natural soil vegetation and underlying.When the rainfall is normal,the traditional dense asphalt concrete pavement is prone to splashing,spraying,glare at night,etc.,which seriously affects driving safety;under heavy rainfall climate conditions,a large amount of road surface runoff will be generated,increasing the burden on the urban drainage pipe corridor,or even cause urban waterlogging.Permeable asphalt pavement can effectively alleviate this problem,so it has been promoted and applied to different degrees at home and abroad.First of all,the combination of theoretical analysis and laboratory experiments is used to design and optimize the mix ratio of permeable asphalt mixtures with different void ratios to determine the gradation of asphalt mixtures and the best oil ratio;through the penetration of permeable asphalt mixtures The test obtained the relationship between the permeability coefficient and the porosity and connected porosity.The permeability coefficient is positively related to the connected porosity.The larger the porosity,the larger the connected porosity and the stronger the drainage capacity;according to the high temperature of the permeable asphalt mixture The stability and water stability indexes were tested,and the results showed that the rutting resistance and water stability of the permeable asphalt mixture decreased with the increase of the porosity.Then,based on the basic theory of seepage and hydrodynamics,using the Seep / w seepage finite element analysis software to simulate the change of water content,permeability coefficient and flow rate with time in the surface and base of the permeable asphalt pavement from the beginning to the end of the rainfall,we obtained curves of different parameters of different layers with rainfall duration and velocity vector cloud diagram of drainage process.Then calculate the critical drainage capacity of the multilane permeable asphalt pavement under different rainfall conditions,analyze the impact of the pavement width,slope,drainage length,and permeability coefficient on the critical drainage capacity of the pavement.It is divided into five grades to evaluate the drainage capacity of multi-lane permeable asphalt pavement under different geometric parameters.Finally,according to the actual rainfall intensity in Chongqing,the target void ratio and the horizontal and vertical drainage pipe spacing settings of the pipe drainage system are calculated,and the feasible suggestions for solving the problem that the void ratio of the permeable asphalt pavement is easy to be blocked in actual engineering are proposed.Through the research of asphalt mixtures with different porosity in Chongqing area,the paper evaluates the drainage capacity of permeable asphalt pavement by the method of test and simulation analysis on the premise of ensuring the road function,which has a certain reference value to the actual project.