论文总字数：24059字

摘 要

近几年海绵城市建设如火如荼，低影响开发（Low Impact Development）设施应用广泛，生物滞留系统是一种从源头削减雨水和控制污染物迁移的高效LID措施。生物滞留系统最大的优点是其适应性和可调控性，该系统除了能渗透补充地下水外，还可实现削减峰值流量、净化雨水，实现径流总量、径流峰值和径流污染控制等多重目标，具有良好的生态效应和水文效应。但对生物滞留系统长期的运行稳定的还缺乏深入系统的研究，其中干湿交替作为生物滞留系统最常见的运行条件，会改变系统内部水力学和生物学特性进而影响生物滞留系统的运行特性。因此，本论文通过实验室模拟，研究干湿交替对生物滞留系统堵塞的影响。

得到以下结论：

（1）干湿交替的湿润期长度增长，会延缓生物滞留池的堵塞进程；渗透系数与干湿交替的相关性更好，干旱条件会使滞留池的渗透系数升高，即缓解堵塞；干旱后的第一天湿润期渗透系数会明显降低，并且生物滞留装置自上而下，其渗透系数变化（即堵塞进程）与干湿交替的基本周期的相关性越来越弱，但温度升高，能够明显扩大干湿交替对下层区域渗透系数变化的影响。

（2）生物滞留池堵塞进程是从最上层开始堵塞，然后自上而下依次堵塞；

（3）干湿交替湿润期长度增加，能够很好的抑制环境温度变化对生物滞留池堵塞的影响；

（4）在高温条件（温度大于30℃）下，干湿交替湿润期长度增加，生物滞留池表层堵塞越严重；

关键词：干湿交替，生物滞留池，渗透系数，孔隙率

Abstract

In recent years, sponge cities have been built in full swing, and low impact development Impact development facilities have also been widely used. The biological retention system is a highly efficient LID measure to reduce the rain and control the migration of the pollutants from source. The greatest advantage of biological retention system is its adaptability and controllability. In addition to permeating and replenishing groundwater, the system can also achieve the objectives of reducing peak flow rate, purifying Rain Water, and realize runoff total amount, runoff peak value and runoff pollution control, etc. It has good ecological and hydrological effects. However, more research is needed on the long-term stability of the biological retention system. As the most common operating condition of biological retention system, the dry and wet alternate will change the hydraulic and biological characteristics of the system which will influence the operating characteristics of the biological retention system. Therefore, in this paper, the effects of dry and wet alternation on the blockage of the biological retention system are studied by laboratory simulation.

The following conclusions were obtained:

1. The increase in the wetting period of dry and wet alternation will delay the blockage process of the biological retention system, and the hydraulic conductivity has a better correlation with the dry and wet alternation. The drought conditions will increase the hydraulic conductivity of the retention system, that is, to alleviate the blockage; the hydraulic conductivity of the first day of the wetting period will decrease obviously, and from top to bottom of the biological retention system, the change of the hydraulic conductivity (that is, the process of plugging) is weaker and weaker in the basic cycle of dry and wet alternation, but the increase of temperature can obviously enlarge the influence of the alternation of dry and wet on the change of the hydraulic conductivity in the lower layer.
2. the blockage process of the biological detention system starts from the top layer, then from top to bottom;
3. the increase in wetting period of wet and dry can effectively inhibit the influence of environmental temperature changes on the clogging of biological detention system.
4. under high temperature conditions (temperature greater than 30 degrees Celsius), the length of dry wet alternate wetting period increases, and the surface plugging of biological detention pond is more serious.

KEY WORDS: alternation of wetting and drying, biological retention system, hydraulic conductivity, porosity.

目录

摘 要 Ⅰ

Abstract Ⅱ

第一章 绪论 1

1.1研究背景 1

1.2生物滞留系统堵塞机理 1

1.2.1物理截留 2

1.2.2生物膜 2

1.2.3化学沉积 2

1.2.4植物根系腐烂 2

1.3 生物滞留系统堵塞影响因素 2

1.3.1进水特征 3

1.3.2填料特性 3

1.3.3温度和溶解氧 3

1.3.4压实度 3

1.4 课题的提出及研究意义 4

1.4.1 课题的提出 4

1.4.2 研究意义 4

1.5 研究内容与技术路线 4

第二章 实验装置及运行条件 6

2.1实验装置 6

2.1.1实验装置 6

2.1.2进水水质及运行条件 7

2.1.3干湿交替基本周期确定 7

2.2实验材料 8

2.2.1植物选取 8

2.2.2基质选取 9

2.3 常规检测项目及方法 9

2.3.1 渗透系数 9

2.3.2 孔隙率 9

第三章 干湿交替对堵塞的影响研究 11

3.1 干湿交替对渗透系数变化的影响 11

3.1.1 生物滞留装置的总体运行规律 11

3.1.2 生物滞留装置A区域各层渗透系数对比 13

3.1.3 生物滞留装置B区域各层渗透系数对比 17

3.2 干湿交替对孔隙率变化的影响 18

第四章 结论与展望 21

4.1 结论 21

4.2 问题与展望 21

致 谢 23

参考文献 24

1. 绪论

1.1研究背景

随着我国城市化进程的加快，城市土地利用的急剧增加，阻止了自然条件下的雨水下渗，从而造成城市地表雨水径流量显著增加、汇流时间缩短，从而使洪峰产生时间急剧缩短。Goyangdae-Ro等^[1]研究发现在自然环境下地表径流占降雨总量的10%，城市区域的地表径流则占55%，而城市雨水管网设计重现期小，导致城市地表径流无法及时排走造成城市内涝，同时产生的还有非点源污染、地下水文环境改变等问题。目前国外对生物滞留池的研究内容主要在集中在以下三个方面：

（1）雨水污染物去除效率的研究，包括营养物、重金属、油脂、悬浮物及致病菌等，特别是对提升N、P去除效率的研究；

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