陶瓷透水砖堵塞及其控制方法研究

针对陶瓷透水砖在应用中广泛存在的堵塞问题,利用自行研发的透水砖雨水径流堵塞实时模拟装置,分别采用自来水和模拟雨水,进行透水砖堵塞试验以及应用3种清洁方式恢复透水砖透水性能试验。在相同径流水量和径流水深条件下,透水砖堵塞主要归结于雨水径流中的颗粒物质在砖表面和内部被截留。堵塞过程分为快速堵塞、回升波动和平稳堵塞3个阶段。根据颗粒物质进入透水砖内部的位置,堵塞可分为表面堵塞和内部堵塞。透水砖表面截留的颗粒质量大于内部截留量,被截留的大部分颗粒粒径<50μm。负压反冲洗、高压水枪冲洗、表面清扫对透水砖透水系数的恢复率分别为76.80%、46.43%、40.52%,三者基本均能完全去除透水砖表面截留颗粒,但后两者无法去除透水砖内部截留颗粒,因此推荐采用负压反冲洗方式控制陶瓷透水砖堵塞。     

玉溪市海绵工程透水砖堵塞规律研究

为研究分析透水砖堵塞规律,采用配制合成的雨水径流模拟透水砖的堵塞过程,考察了透水砖初始透水系数、透水柱进水水位高度及堵塞溶液SS浓度对透水砖透水系数的影响。实验结果表明,透水砖堵塞过程分为快速堵塞、小幅恢复和慢速堵塞三个阶段,透水砖初始透水系数较大、透水柱进水水位较高、堵塞溶液SS浓度较低时,透水砖堵塞相对缓慢;经过长时间堵塞,透水砖最终透水系数相近。研究透水砖的堵塞规律,对透水砖在海绵城市建设中的推广使用具有一定的意义。     

不同颗粒级配的风积沙对陶瓷透水砖性能的影响

以巴丹吉林沙漠的风积沙为原料,添加一定量的粘结剂、助熔剂、糊精混合压制成型,通过高温烧结制备风积沙陶瓷透水砖。分析了不同粒径风积沙的化学和晶相组成及相对含量,分别研究了风积沙的粒径和添加量对陶瓷透水砖透水系数、抗折强度及微观形貌的影响。结果表明:风积沙的粒径对陶瓷透水砖的抗折强度起主要作用,风积沙的添加量对陶瓷透水砖的透水系数影响较大。当风积沙的颗粒级配为40～60目(0.25～0.38 mm),添加量85%时,制备的陶瓷透水砖性能最佳:透水系数为1.62×10-2cm/s,抗折强度为3.13 MPa。制得的风积沙透水砖强度高且透水性能好,可应用于海绵城市建设。     

透水混凝土路面结构层孔隙堵塞机理试验研究

利用透明聚丙烯酸钠小球代替透水混凝土粗集料,对堵塞颗粒在地表径流作用下进入透水混凝土内部孔隙造成的堵塞过程进行了图像分析研究,并采用控制变量法分别研究了透水混凝土孔隙率、水平径流速度、渗流速度、堵塞颗粒级配对堵塞过程的影响。结果显示:堵塞过程经历了快速堵塞、堵塞恢复、缓慢堵塞和稳定堵塞4个阶段;孔隙率和堵塞颗粒级配对堵塞发展速度的影响较为明显;孔隙率、水平径流速度、渗流速度和堵塞颗粒级配都对各粒径堵塞颗粒的最终分布有一定影响。该研究结果对透水混凝土路面的养护有一定的参考价值。     

地表径流污染物在透水铺装系统中的迁移规律

针对北京市雨水径流特性,选取3种典型的透水铺装系统即水泥透水砖、砂基透水砖和页岩透水砖,以面层破损实验和柱实验方式研究透水铺装系统对常规径流污染物（COD、NH₄⁺-N、TN、TP）的去除效能和机制,探讨不同降雨重现期和透水铺装各床层的影响。结果表明,破损的面层材料经雨水浸泡后可能会出现污染物溶出现象,加剧径流污染。3种透水铺装系统出水中的径流污染物浓度变化趋势基本一致,随着运行时间的延长,大部分污染物的浓度先急剧降低随后出现不同程度的升高。水泥砖和砂基砖透水铺装系统对污染物的去除效能较为接近,均优于页岩砖透水铺装系统。3种透水铺装系统面层、基层下部以及底基层对COD和NH₄⁺-N的去除效果较好;系统各床层对TN的去除效果均较差,甚至出现TN析出的现象,但对TP的去除效果均较好。当降雨重现期增加时,透水铺装系统对污染物的去除效果变差。     

运用响应面法对透水混凝土堵塞试验分析

透水混凝土作为海绵城市建设排水工程中的透水铺装、排水明沟及生物滞留设施建设重要材料,得到了广泛推广和应用,但透水混凝土在长期使用后,其具有的多孔性特质导致堵塞物质随地表径流进入孔隙,堵塞现象不断加剧导致透水混凝土透水性功能丧失。针对堵塞涉及的雨水径流水头高度、水平径流速度和试件孔隙率三个关键影响因素开展试验和模拟分析,探讨应用响应面软件研究透水混凝土的堵塞规律。试验结果表明:雨水径流水头的高度对孔隙堵塞影响性最高,而孔隙率和水平径流速度的交互作用对孔隙堵塞的影响程度显著。     

基于FLUENT天然气集输管道直角弯管磨损分析

应用Fluent软件对直角弯管磨损情况进行数值模拟,研究天然气集输过程中有浮升力和无浮升力条件下不同颗粒直径、不同气流流速条件对弯管磨损的影响,研究结果表明:无浮升力和有浮升力条件下,随着粒径增大,弯管壁面的1.5 s累计最大冲蚀量先减小后逐渐增大,粒径小于50μm的微小颗粒对管壁的冲蚀磨损程度较小。有浮升力条件下,管道壁面的1.5 s累计冲蚀量有所增大,这是由于颗粒在浮升力作用下更多地碰撞弯管壁面。无浮升力和有浮升力条件下,随着粒径增大,弯管壁面的1.5s累计最大沉积量先快速下降而后缓慢增加。有浮升力的条件下,颗粒运动对壁面的沉积效应有所缓解,随着粒径的不断增大,浮升力对管壁的沉积影响逐渐变小。较小粒径的颗粒受浮升力影响在管道沉积方面表现更为敏感。无浮升力和有浮升力条件下,随着气流入口流速的不断增大,弯管壁面的1.5 s累计最大冲蚀量逐渐增大。有浮升力条件下,当入口流速增大时,增大的浮升力导致颗粒跳跃增多,浮升力作用增强了颗粒对弯管壁面的冲蚀破坏。无浮升力和有浮升力条件下,随着气流入口流速的不断增大,弯管壁面的1.5 s累计最大沉积量呈现先减小后逐渐增大的趋势。有浮升力条件下,入口流速增大时,边界层内速度梯度使颗粒旋转而产生更大的浮升力,致使颗粒的沉积量减少。但随着入口流速的继续增大,边界层厚度逐渐变薄,,浮升力的影响作用减小,颗粒沉积量增大。合理控制入口流速能够有效减少管道磨损。     

重矿渣-砂基复合透水路面砖的研究及制造

重矿渣-砂基复合透水路面砖是水泥基与环氧树脂体系的复合产物,在传统水泥透水砖的基础上,采用改性环氧树脂胶作为胶粘剂,天然彩砂为骨料制备面层。通过正交实验得出了影响其性能的因素的主次顺序,得出最优配合比为:胶砂比1∶30,成型压力25kN,骨料粒径40～80目,改性环氧树脂胶黏度为80mPa·s。所制得的透水砖劈裂抗拉强度f_(ts)为4.2MPa,透水系数为1.9×10~(-2) cm/s,磨坑长度10mm,抗冻融性合格。既实现了工业废渣的资源化利用,又在一定程度上解决了传统透水路面砖易堵塞难恢复,服役时间短的弊端。同时给出了工业化生产砂基复合透水路面砖的工艺参数。     

透水砖堵塞和控制研究及应用进展

透水砖是海绵城市系统的重要组成部分,可有效降低城市雨洪风险。但透水砖会因截留颗粒物而降低其渗透性能,严重缩短其使用寿命。综述了透水砖的分类、堵塞机理、防堵控制技术,及其在我国的工程实践应用情况。透水砖堵塞位置和程度主要受材料、孔隙结构、雨水径流颗粒物性质及暴露环境等诸多因素共同影响,需要经常性的维护清理以保证其透水性能。目前,透水砖主要有人工清扫、高压冲洗和真空抽吸等三种维护方法,但只能去除透水材料表层截留物,恢复能力有限。因此,研制高强度和高渗透性的透水砖,以及与纳米科技应用和耦合系统有助于源头控制堵塞。最后对缓堵型透水材料研制和长效维护机制提出了研究建议。     

全钢渣集料透水砖基本性能研究

为研究全钢渣集料对透水砖性能的影响,以粗钢渣取代粒径和水灰比为影响因素,开展全钢渣集料透水砖透水系数和抗压强度试验研究。结果表明：全钢渣集料透水砖的透水系数随着粗钢渣取代粒径的增大先增大后减小,随着水灰比的增加逐渐增大;抗压强度与粗钢渣取代粒径成正相关,与水灰比成负相关。在试验基础上,提出全钢渣集料透水砖透水系数和抗压强度的计算式。     

Clogging of stormwater gravel infiltration systems and filters: insights from a laboratory study

Stormwater infiltration systems are widely used in the control of polluted urban runoff. They are very effective in reducing the volume of stormwater runoff and improving its quality, but they are known to be prone to clogging. Whilst it is evident that clogging determines the design lifespan of infiltration systems, quantitative understanding of the clogging process is currently very limited. A laboratory study was therefore undertaken to better understand physical clogging processes, with the ultimate aim of developing a clogging model for stormwater infiltration systems. This paper presents findings from one-dimensional (1-D) experiments conducted on a gravel filter column. Physical clogging was studied under both constant and variable water levels, and for different sediment inflow concentrations. It was found that a clogging layer forms at the interface between the filter and underlying soil, irrespective of the inflow regime of both water and sediment. It was also found that clogging is much slower if the water level is kept at a constant level than if it varies within the column, due to formation of a sediment plug that 'shelters' the filter/soil interface. Most importantly it was shown that physical clogging is mainly caused by migration of sediment particles less than 6 microm in diameter. A simple regression model was proposed and tested for the prediction of clogging due to stormwater sediment.     

透水砖和下凹式绿地对城市雨洪的影响

为考察不同雨洪措施对防洪和增加雨洪资源利用量的贡献,采用城市暴雨雨水管理模型(SWMM),对北京某区域内铺设透水砖和采用下凹式绿地措施的排水管道主要断面洪峰流量的变化进行了计算分析。结果表明,铺设透水砖和采用下凹式绿地均可有效削减洪峰流量,减小径流系数,从而增加雨洪资源的利用量。但对于不同降雨频率的地区,下凹式绿地在降雨频率较大的地区,雨洪利用效果较好;透水砖则在降雨频率较小的地区,雨洪利用效果较好。该研究成果可以用来评价不同雨洪措施在不同降雨频率下对城市雨洪的利用效果,为防洪排涝工程提供了一定的技术支持。     

IN-SITU HYDRAULIC PERFORMANCE OF A PERMEABLE PAVEMENT SUSTAINABLE URBAN DRAINAGE SYSTEM

There is growing awareness that sustainable urban drainage systems can offer a more sustainable option for the management of stormwater runoff than conventional drainage systems. This paper presents in-situ performance data from a permeable pavement system which was installed to collect and treat stormwater runoff from a motorway servicestation car park. Data on rainfall at the site and outflow from the permeable pavement were collected over a thirteen-month period, and twenty rain events were studied in detail. The system provided a large degree of attenuation in terms of (a) reduction in peak flows, and (b) extended duration of outflows compared with rain events. Infiltration tests provided information on the processes of water entry into the pavement system and impacts of clogging on hydraulic performance.     

城市绿地对雨水径流污染物的削减作用

为探究城市绿地调控城市降雨地表径流污染的有效性和可行性,采用室内土柱模拟试验,研究植被覆盖、径流污染物浓度、土壤层深度、地下水、水力负荷与停留时间对城市绿地削减污染物的影响。结果表明,在低、中和高3种 雨水径流污染物浓度水平（CODCR 为68、137、550 mg/L;TN是3.01、7.51、30.06 mg/L;TP为0.29、0.69、2.73 mg/L; NH+4是0.44、1.61、2.19 mg/L）,水力负荷为3.5、3.0、2.5 cm/h,持续进水1 h条件下,城市绿地具有良好且稳定的污染削减能力,对CODCR 、TN、TP、NH+4的平均削减率分别达到41.52%、78.96%、84.68%,50.21%、70.23%、60.91%,73.18%、95.88%、94.99%,62.72%、55.16%、69.98%。受土壤复氧能力和水力停留时间的限制,绿地覆盖对污染物CODCR 与TN削减率的影响不明显。城市绿地污染削减率随着降雨地表径流污染物浓度的升高而呈现逐渐增加的趋势。城市绿地对雨水地表径流污染削减作用主要发生在深度35~65 cm土层内。城市绿地对低、中和高污染浓度水平各污染物削减率随着水力负荷的增加而降低。     

Stormwater runoff quality and quantity from asphalt, paver, and crushed stone driveways in Connecticut

This study compared the quality and quantity of stormwater runoff from replicated asphalt, permeable paver, and crushed-stone driveways. Rainfall was measured on-site and runoff was recorded using tipping buckets. Flow-weighted composite runoff samples were analyzed weekly for total suspended solids, total Kjeldahl nitrogen, nitrate-nitrogen, ammonia-nitrogen, total phosphorus (TP), zinc, lead, and copper. Infiltration rate was determined on each driveway annually. Repeated measures analysis of variance indicated that stormwater runoff was significantly different among each driveway type; the order of decreasing runoff was asphalt> paver> stone. Average infiltration rates were 0, 11.2 and 9.0 cm/h for asphalt, paver, and crushed stone driveways, respectively. Both paver and crushed stone driveways reduced stormwater runoff as compared to asphalt driveways. Runoff from paver driveways contained significantly lower concentrations of all pollutants measured than runoff from asphalt driveways. However, runoff from crushed stone driveways was similar in concentrations to runoff from asphalt driveways, except for TP concentrations, which were lower in runoff from crushed stone driveways than runoff from asphalt driveways. The mass export of measured pollutants followed the relative differences in stormwater runoff, rather than differences in concentrations.     

Suspended particle characteristics in storm runoff from urban impervious surfaces in Toowoomba,Australia

Total suspended solids as a measure of suspended particles in urban stormwater has limitations and the alternative suspended sediment concentration method was adapted to determine non-coarse particle (NCP) concentration, defined as particles smaller than 500 μm. NCP was partitioned into the following classes: very fine particles (<8 μm, VFP), fine particles (8–63 μm, FP) and medium particles (63–500 μm, MP). A site mean concentration approach was adopted to differentiate the suspended particle characteristics between three impervious surfaces (roof, road and car park) using runoff data collected for 35 storms. Runoff particle size distribution (PSD) of all surfaces was dominated by particles less than 63 μm. A weak trend of relatively constant VFP concentration was present in the road runoff data. Roof runoff PSD became finer as NCP concentration increased and, overall, the PSD of car park runoff was coarser compared to road and roof runoff. These findings have runoff treatment implications as settling processes are influenced by particle size.     

不同下垫面暴雨径流氮赋存形态分布特性及控制技术

以重庆地区5种用地类型为例,探讨了城市暴雨径流中氮赋存形态的分布特性.研究结果表明,总氮的场次降雨平均浓度(Event Mean Concentrations,EMCs)以交通干道最高(10.6 mg/L),校园汇水区最低(2.4 mg/L);交通干道和商业区暴雨径流氨氮的EMCs(3.4～4.6 mg/L明显大于水泥屋面和瓦屋面(1.2～1.6 mg/L).尽管初期暴雨径流总氮的平均浓度(Partial Event Mean Concentrations,PEMC10)大于EMCs,但氮赋存形态构成并未发现明显区别;氮以溶解性总氮为主(占总氮的73％～82％),而溶解性总氮中又以无机氮为主(占总氮的63％～82％);商业区、水泥屋面、校园综合汇水区、瓦屋面暴雨径流中氮赋存形态所占比例最高的均为硝酸根,分别占各自总氮浓度的39％、39％、44％和52％,而城市交通干道的总氮浓度中比重最大的组分为氨氮,占总氮的43％.改良暴雨管理措施可有效提高暴雨径流中总氮的去除率,其关键为人工创造反硝化所需要的条件,延长暴雨径流在控制系统内的水力停留时间,并选择低氮含量的填料作为控制系统的使用材料.     

Effects of PVC,cast iron and concrete conduit on concentrations of copper in stormwater

Architectural applications of copper on roofs, gutters and facades exposes it to weathering forces, such as wind and all forms of precipitation. This leads to the dissolution of copper from these surfaces and its introduction into local watersheds. The potential for exposure in local watersheds is a function of the amount of copper entering the watershed and the assimilation capacity of a wide variety of natural and manmade substrates that transform and sequester copper, thus reducing exposure of sensitive organisms to bioavailable copper. This study investigates one type of manmade substrate, stormwater conduit, commonly used to transport stormwater away from buildings. Conduits made of PVC and cast iron did not significantly remove copper from a synthetic stormwater spiked with copper averaging 2391 μg Cu/L. Concrete conduit significantly removed copper from the synthetic water and at high rates (12 – 18%) over a short distance (610 cm). A high percentage (81 – 100%) of the copper removed from the water was from the dissolved copper fraction. Once adsorbed to the concrete, copper did not readily leach back into copper-free water subsequently pumped into the conduit. These characteristics have significant implications for watershed management and best management practices for reducing concentrations of copper in stormwater runoff.     

新型渗井-透水网格措施的径流调控效果研究

为更加合理地对雨水资源进行管理和调控,低影响开发(LID)措施日益成为我国许多城市"海绵化"的必然选择。透水网格被认为是一种有着良好雨洪管控效用的LID措施,然而大多情况下施工过程不尽规范,土基多采用渗透性不良的土质,这使得径流调控及渗流效益难以充分发挥,故拟以透水网格砖孔布设渗井来改善该现状。采用试验与SWMM仿真相结合的方法,研究了在6场重现期降雨作用下新型渗井-透水网格措施较透水网格在径流调控方面的改善效果,以及100年重现期降雨条件下两种措施的入渗规律。结果表明,在不同降雨场次下,新型措施较透水网格雨量径流系数降低了9.94%~51.09%,洪峰流量削减率提高了2.91%~30.42%;滞峰时间延迟效果不显著,在3 min以内;在100年重现期降雨下湿润锋迁移速率提高了73.47%。     

微孔生态透水材料的制备及性能研究

以沙漠中风积砂为主要骨料,通过免烧结压制成型,研制了一种微孔生态透水材料预制件,并对其性能进行测试。结果表明:当孔隙率为15%左右,胶凝剂掺量为4.5%时,所制备透水材料的透水系数达2.3×10^-2 cm/s,抗压强度为32.7 MPa;透水砖对城市路面径流污水中40~70μm的悬浮物(SS)去除率达75%以上。与其它透水材料相比较,该透水产品透水时效长、吸声降噪性能强、铺装性价比高。