排水沥青路面超渗流行为时空分布规律的试验研究

Experimental Study on Spatio-temporal Distribution of Excess-infiltration Behavior of Permeable Asphalt Pavement

为探究排水沥青路面在不同降雨环境下真实的超渗流行为,并弥补现有渗水试验表征排水能力的不足,以目标空隙率为20%和22%、公称最大粒径为13.2 mm的排水沥青混合料(PAC-13)为研究对象,基于自主研发的降雨排水试验装置,采用降雨峰值比例为0.4、降雨历时为30 min的广州地区芝加哥雨型进行室内降雨试验和数据分析;探明重现期分别为0.5,1,2,10,50,100 a的降雨强度下,合成坡度为2.5%的路面超渗流行为时空分布规律;提出以极限降雨强度、超渗流水位曲线和径流时间参数来综合评价排水路面的排水性能。结果表明:(1)自主研发的降雨排水装置能得到排水沥青路面超渗流行为的时空分布规律;(2)20%和22%空隙率试验组的极限降雨强度分别为1.6 mm/min和2.0 mm/min,试验最大径流均出现在峰值降雨阶段,出现的位置一般在距离道路中心线0.7~1.5 m之间;(3)提升空隙率可以在一定程度上减少径流量的大小;(4)超渗流水位曲线越平缓,其内部渗流越流畅,排水能力越好;(5)超渗流水位曲线越集中,其排水能力越接近极限;(6)增加空隙率对路面径流的水膜厚度影响有限,但对路面径流的持续时间有着良好的削减作用,重现期越长这种削减作用越强,同时还能降低径流量持续时间随着重现期的增大而增加的速率。

In order to explore the actual excess-infiltration behavior of permeable asphalt pavement under different rainfall intensities,and to make up for the deficiency of the existing infiltration test to characterize the drainage capacity,the permeable asphalt concrete with nominal maximum particle size of 13.2 mm(PAC-13)is taken as the study object.Based on the self-developed rainfall drainage test device,the indoor rainfall test and data analysis are carried out on PAC-13 with target void ratio of 20%and 22%by using Chicago rain pattern in Guangzhou with rainfall peak ratio of 0.4 and rainfall duration of 30 min.The spatiotemporal distribution of excess-infiltration behavior of porous asphalt pavement with synthetic slope of 2.5%under rainfall intensity with return periods of 0.5,1,2,10,50,100 a is investigated.It is proposed to comprehensively evaluate the drainage performance of permeable asphalt pavement with the parameters of excess-infiltration water level curve,runoff time parameter and ultimate rainfall intensity.The result shows that(1)the self-developed rainfall drainage device can obtain the spatio-temporal distribution rule of the excess-infiltration behavior of the permeable asphalt pavement;(2)the ultimate rainfall intensity of 20%and 22%porosity test groups are 1.6 mm/min and 2.0 mm/min respectively,the maximum runoff of the test appears in the peak rainfall stage,and the location is generally between 0.7 m and 1.5 m from the center line of the road;(3)increasing the porosity can reduce the size of runoff to a certain extent;(4)the more smooth-out the excess-infiltration water level curve is,the smoother the surface seepage is,and the better the drainage capacity is;(5)the more concentrated the excess-infiltration water level curve is,the closer the drainage capacity is to the limit;(6)increasing the void ratio of porous asphalt pavement has limited influence on the water level height of road surface runoff,but has a good reduction effect on the duration of road surface runoff.The greater the return period,the stronger the reduction effect.At the same time,it can reduce the rate at which the runoff duration increases with the increase of the return period.