源位生态渗-滤技术阻滞道路径-渗流污染的作用机理及方法

As typical non-point source pollution, prevention and control of water pollution in road pavement runoff and seepage has become an important issue of ecological road construction. Reduction from source pollution is considered to be the primary link of pollution control. However, studies emphasized on pollution investigation and treatment technology and results in China is still in the initial period. So the mechanism, related theories and methods of road pavement runoff and seepage pollution need to be explored urgently. Pollution distribution characteristics of traditional and ecological road pavement runoff and seepage were studied firstly. In order to increase the migration types and prolong the concentration change path, road pavement runoff and seepage of contaminants block such as purification water permeability material layers, vegetation ecological slopes and layered filtration devices will be designed. Moreover, effects of road functional modules' materials and composition on the contaminants filtering will be also studied through the laboratorial runoff and seepage simulation system. The migration model of road pavement runoff and seepage pollution in all types of surface material will be established based on porous media seepage and the pollutant migration theory. Considering effects of pore-hydraulic factors on the long-term pollutants filtering impact, means including BET test theory, IR, SEM, etc. are adopted to analyze the pollutants solidifying and obstruction mechanism during the process of road pavement runoff and seepage path from input to output. This research aims to provide a theoretical basis and technical support to the prevention and control of roads water pollution, as well as targeted road ecological construction.

作为典型的面源污染，道路路面径-渗流水污染防治已成为道路生态建设的重要问题。源头污染减量研究被认为是非点源污染控制的首要环节，但其处治机理及相关理论和方法亟需完善。本项目拟在对传统道路与新型生态道路路面径-渗流污染分布特征调研的基础上，针对透水沥青路面、透水性材料净化层、大孔隙植生混凝土护坡及生态滤沟等路域范围内源位滞蓄渗滤措施进行优化组合；通过实验室道路-降雨模拟系统足尺加速试验，研究各滞蓄渗滤结构材料及其组成对径-渗流净化效果的影响，分析污染物随径-渗流在各滞蓄渗滤结构中的运移特性；基于多孔介质渗流理论，建立径-渗流污染物在道路各类下垫面介质中的运移模型；考虑孔隙-水力双重因素对污染物长期阻滞作用的影响，运用BET、红外光谱、扫描电镜等微观测试手段，分析道路雨水从输入到输出路域过程中的污染物净化、空隙堵塞机理。为道路水体污染治理与控制及有针对性的道路生态化建设提供理论基础与技术支持。

路面径流排放、下渗对周围水系和地下水环境造成的影响已经成为道路生态化建设亟待解决的重要问题。本报告通过大量文献与实地调研，在综合比对多种污染处治措施的基础上，提出了基于渗滤系统和透水铺装等原位污染控制技术，通过“径流转变为渗流”实现道路面源污染净化的基本思路，并设计了合理的净化介质与渗流路径，从试验、数值层面论证了路面径流污染原位控制技术的可行性。.通过实地采样与测试，对水泥混凝土、密实沥青混凝土、透水沥青混凝土三种不同道路路面形式的产流过程、径流污染物浓度水平与时空分布特征进行了探究，发现水泥混凝土路面和密实沥青混凝土路面的产流过程为“冲刷-浸润-径流”，透水沥青混凝土路面的产流形式为“冲刷-浸润-渗流-径流”。.研究设计了“全渗透式”道路断面的基本形式，确定了包括透水沥青混凝土路面、多孔水泥混凝土边坡、矿物材料净化层和生物废料改良土4种净化介质组成的渗流路径，对不同配（合）比的净化介质进行了室内制备、基本性能测试，确定了干法撒布沉积土与湿法化学试剂法投放相组合的污染物输入方式，并设计、开展了不同配（合）比的净化介质的室内净化试验。.对净化前后径流水样中悬浮颗粒粒径范围、峰形特征及最频粒径的变化规律进行了分析，发现透水沥青混凝土主要截留大粒径颗粒，多孔水泥混凝土主要截留大粒径和中等粒径的颗粒，而矿物材料净化层对各个粒径范围的颗粒均具有较好的截留作用。.建立了道路结构及其地下水环境的有限差分模型和污染物运移模型，初步探究了路面径流入渗部分对其污染羽的影响，运行结果表明：污染物在道路及其地下水环境中的入渗与迁移过程受到介质分界面、地下水位线、距离排水区域的距离等因素的影响，表现出有规律的时间、空间的累积现象。.根据净化介质的初始净化能力，绘制了初始净化等级示意图，并从空间布局、层位布局、材料混合、净化增强四个层面给出了适用于不同污染物浓度水平与净化等级要求的净化介质组合方法。