透水路面非饱和状态排水时间数值分析

Numerical Analysis on Drainage Time at Unsaturated State for Permeable Pavements

关于透水路面排水质量评价及排水路面结构的设计,我国现行《公路排水设计规范》是基于饱和流理论,认为在降雨期间和降雨后的路面结构都是处于饱和状态,渗透系数是固定值。实际上,路面结构处于饱和状态下的时间是非常短暂的,仅仅是在降雨过程中排水层的含水量达到了饱和并且形成稳定流态这段时间,而大多数情况下的路面结构都是非饱和状态。本文基于Van Genuchten模型,提出了非饱和状态下的排水时间数值计算方法,使得透水路面排水性能的评价更为合理。

With regard to drainage performance assessment and structural design of permeable pavement,the currently implemented specification is based on saturated flow theory,which supposes that constant called saturated permeable coefficient and pavement structure is on a saturated condition in or after raining. Nevertheless,pavement structures on a saturated condition will last for a very short time. In another word,the pavement structure is on a saturated condition and forms a steady flow only when raining,which means in most cases the pavement structure is on unsaturated condition. To make the evaluation of permeable pavement performance more reasonable,this paper proposes a numerical calculation method for permeable pavement drainage time on unsaturated condition based on the Van Genuchten model.