渗流作用下的透水路面雨水净化机理与储水-渗透模型

With purpose of addressing the negative influence of close-graded paved roads on the ecological environment, this proposal herein presents a research approach to study rain purification and water storage-infiltration model of permeable pavement based on materials and structure characteristics of permeable pavement. Both CT testing and digital image processing techniques will be jointly employed in this research to study the microscopic void characteristics and infiltration law of the porous pavement materials. As a result of this research, the following objectives will be reached: 1) the underlying principles on which macro materials' composition characteristics of porous pavement materials influence the penetration ability and microscopic void characteristics will be revealed; 2) the constitutive relationship among the composition of the mixture, microscopic void characteristics and penetration ability will be established. Additionally, Based on the studies of microscopic void characteristics, this research will analyze how the space distribution of the void and microscopic structure influence the purification mechanism and efficiency of the suspended solid (SS) and organic pollutant (COD) in infiltration rainwater. The findings of this research will finally optimize the design of both the materials composition and structure combination of permeable pavement.. Finally, based on the water dynamics and seepage theory, this research will establish water storage-infiltration model. The model parameters may include void structure, pavement structure, and meteorology factors. The research objective is to study the influence that air void, penetration ability, structure thickness and rainfall duration/ return period of heavy rain made on the water saving-permeating performance in the porous pavement. With permeable pavement materials' properties as inputs, this study will propose a method for selecting permeable pavement materials and structure according to different function requirements and regional weather characteristics. Compared with the existing studies in this area, the proposed study herein will provide theoretical and technical support for the application of the porous pavement.

针对目前城市密实铺装路面带来的生态环境负面影响，本项目以透水路面材料与结构特征为基础，研究透水路面雨水净化和储水-渗透模型。结合CT检测和数字图像处理技术，研究多孔路面材料细观空隙特征和渗透规律，揭示多孔路面材料宏观材料组成对其细观空隙特征和渗透能力的影响规律，建立混合料材料组成-细观空隙特征-渗透能力的本构关系；基于细观空隙特征的研究结果，分析空隙的空间分布、细观构造对入渗雨水中悬浮固体SS和有机污染物COD的净化机理与效能，优化透水路面材料组成和结构组合设计；基于水动力学和渗流理论，构建包含材料空隙构造、路面结构和气象学参数的透水路面储水-渗透模型，研究空隙率、渗透能力、结构厚度和降雨历时/暴雨重现期等参数对透水路面中雨水储留-渗透效能的影响，结合透水路面材料特性，提出基于功能要求和地域气象特点的透水路面材料和结构选型方法。为透水路面的应用提供理论和技术支撑。

相对于目前以密实型路面铺装为主的城市道路，透水沥青路面能够补充地下水；同时，透水沥青路面连通了城市地下和上部空间，能够调节大气湿度，利于植物生长，缓解城市热岛效应。此外，透水路面还能够减小暴雨时的洪峰流量，减轻城市排水系统压力；降低车辆行驶噪声，改善道路行驶的安全性。.研究中，基于CT、图像处理及重构技术和室内试验分析了多孔沥青混合料细观空隙特征表征，研究了空隙率、粗细级配和公称最大粒径等对多孔沥青混合料细观特征的影响规律及细观空隙特征同混合料性能间的关系；研发了试验装置模拟地表径流入渗路面结构的过程。通过测在地表径流在渗入透水路面结构前和渗出后不同采集时间的水样中16项污染物指标，评价路面对入渗地表径流中污染物的去除效果，揭示了不同污染物的去除机理。基于气象学和水力学理论建立透水沥青路面的储水-渗透模型，提出相应的功能设计目标，并对透水路面的效能进行计算和分析。.研究结果表明空隙率会对多孔沥青混合料的路用性能和功能产生影响。从宏观上其原因在于级配粗细和公称最大粒径的变化，从细观角度看，多孔沥青混合料空隙等效直径的变化则是影响多孔沥青混合料路用性能和功能的重要因素。混合料断面图像的空隙等效直径、空隙面积、空隙数量、空隙分形特征同混合料的材料组成与性能密切相关；对于空隙率相近的多孔沥青混合料，其细观空隙特征同混合料动稳定度、飞散损失和吸声系数峰值具有良好的回归关系。透水沥青路面结构对重金属污染物、石油类、动植物油类的有机污染物的过滤净化效果最好，对BOD、COD、氨氮、总磷等营养盐的过滤净化效果次之，而对氯化物、TN等无机阴离子和和营养盐的净化效果不佳。通常随着水样采集时间的延长，水体中污染物含量都有不同程度的降低。透水路面去除雨水中污染物的机理主要是通过截留和物理吸附作用。所构建的透水路面储水-渗透模型能够针对不同地域的气象和降雨特点对路面的储水、渗透功能进行预估和评价；透水沥青路面最大储水量出现时间滞后于最大降雨强度发生时间；当透水路面结构不满足该降雨条件下的储水和渗透功能要求时，可增大路面储水结构层厚度，或铺设纵向排水管道。.研究成果对于揭示多孔路面材料组成、路用性能和功能之间的内在关联，从材料细观特征的角度指导多孔沥青混合料性能和功能设计具有显著意义；同时所构建的透水路面储水-渗透模型能够预估和评价透水路面的储水功能和渗透效能，指导透水路面结构和排水系统设计。

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