Changing characteristics and influencing factors of Manning's roughness coefficient along grass swales
-
摘要:
随着海绵城市的快速发展，植草沟得到了广泛应用。目前关于植草沟沿程流量的计算一般采用谢才公式，但其适用条件与植草沟存在显著差异，导致计算结果存在一定误差，其中曼宁粗糙系数变化是引起误差的原因之一。在假定谢才公式适用的前提下，通过足尺试验，系统研究了恒定流量、变流量进水条件下植草沟曼宁粗糙系数的变化特征，并进一步分析了植被高度对曼宁粗糙系数的影响。结果表明：植草沟沿程流量以及曼宁粗糙系数均随流动距离增加而降低；不同进水流量条件下，曼宁粗糙系数与进水流量密切相关，随进水流量增加而增加，试验条件下其最大值为0.22；另外，在植草沟不同植被高度以及不同变流量进水条件下，曼宁粗糙系数在峰值流量时刻的变化范围为0.19~0.22，试验条件下植被高度对曼宁粗糙系数影响较小。因此，植草沟的曼宁粗糙系数受沿程流量的影响较大，研究成果可以为植草沟沿程流量计算时曼宁粗糙系数的精确取值提供参考。
Abstract:With the rapid development of sponge cities, grass swales have been widely used. Recently, the Chezy formula is generally used to calculate the flow rate along the grass swales. There are differences between the application conditions of the Chezy formula and grass swales, which often cause remarkable calculation errors. One of the reasons for the errors is the Manning roughness coefficient variation. Assuming that the Chezy formula was appropriate, the variation characteristics of the Manning roughness coefficient of grass swales under different constant and variable inflow conditions were systematically researched through full-scale experiments, and the effect of vegetation height on the Manning roughness coefficient was further analyzed. The results showed that the flow rate and Manning roughness coefficient decreased with the increase of flow distance along the grass swale. Under different inflow conditions, the Manning roughness coefficient was closely related to the inflow rate, and the higher the flow rate, the greater the Manning roughness coefficient, with the maximum value being 0.22. In addition, the maximum Manning roughness coefficient of grass swale with different vegetation heights was 0.19-0.22 under different variable flow inflow conditions, and the vegetation height had little influence on the Manning roughness coefficient under the experimental conditions. Therefore, the Manning roughness coefficient of grass swale was markedly affected by runoff volume. The research results can provide reference for selecting the Manning roughness coefficient in the calculation of grass swale drainage capacity.
-
图 1 植草沟试验装置
1—进水箱；2—进水管；3—电磁流量计；4—配水槽；5—溢流挡板；6—堰；7—植草沟；8—出水槽；9—出水箱；10—水泵；11—橡胶管；12—回流管。
Figure 1. Experiment device of grass swale
图 2 不同降雨重现期条件下植草沟进水流量过程线
Figure 2. Inflow hydrograph of grass swale under different rainfall return periods
图 6 植草沟沿程实测流量和理论流量
Figure 6. Monitored and theoretical calculated flow rates along grass swale
图 7 植草沟内沿程流量和n变化
Figure 7. Changes of flow rate and Manning roughness coefficient along grass swale
图 8 植草沟不同沿程距离n变化特征
Figure 8. Variation characteristics of Manning roughness coefficient at different monitoring locations along grass swale
图 9 植草沟植被高度在不同沿程距离处对峰值流量时刻n的影响
Figure 9. Effect of vegetation height on Manning roughness coeffiencent at peak flow time of different monitoring locations
表 1 不同恒定Q进下植草沟沿程n衰减率
Table 1. Manning roughness coefficient attenuation rate along grass swale under different constant inflow rates
% 植草沟沿
程距离/mQ进/(m3/h) 1 1.5 2 3 4 5 19.7 8.3 6.6 2.9 3.7 10 40.5 20.0 12.9 5.6 4.8 15 51.2 35.5 20.1 8.8 6.5 20 71.5 45.2 26.4 12.2 9.5 
下载: 导出CSV
-
[1] 李凯, 王建龙, 林宏军, 等.生物滞留设施排空时间影响因素研究[J]. 环境工程技术学报,2022,12(1):240-247. doi: 10.12153/j.issn.1674-991X.20210156LI K, WANG J L, LIN H J, et al. Study on the influencing factors of emptying time of bioretention facilities[J]. Journal of Environmental Engineering Technology,2022,12(1):240-247. doi: 10.12153/j.issn.1674-991X.20210156 [2] 朱文彬, 孙倩莹, 李付杰, 等.厦门市城市绿地雨洪减排效应评价[J]. 环境科学研究,2019,32(1):74-84.ZHU W B, SUN Q Y, LI F J, et al. Assessment of the effect of urban green space landscape on reduction of storm water runoff in Xiamen City[J]. Research of Environmental Sciences,2019,32(1):74-84. [3] Maryland Department of Environmental Resources Programs and Planning Division. Low-impact development: an integrated design approach[R]. Washington DC: US EPA, 1999. [4] PITT R, NARA Y, KIRBY J, et al. Particulate transport in grass swales[C]//Low impact development. Wilmington: American Society of Civil Engineers, 2008: 191-204. [5] 张瑞斌.2种生态植草沟对路面径流净化效果的对比[J]. 环境工程技术学报,2021,11(3):493-498. doi: 10.12153/j.issn.1674-991X.20200181ZHANG R B. Comparison of the effect of two kinds of ecological grass swales on road runoff purification[J]. Journal of Environmental Engineering Technology,2021,11(3):493-498. doi: 10.12153/j.issn.1674-991X.20200181 [6] 王书敏, 郭树刚, 何强, 等.城市流域降雨径流水质特性及初期冲刷现象[J]. 环境科学研究,2015,28(4):532-539. doi: 10.13198/j.issn.1001-6929.2015.04.07WANG S M, GUO S G, HE Q, et al. Water quality characteristics of stormwater runoff and the first flush effect in urban regions[J]. Research of Environmental Sciences,2015,28(4):532-539. doi: 10.13198/j.issn.1001-6929.2015.04.07 [7] 张炜, 郝巍魏, 闫文博, 等.进水水力负荷对植被浅沟雨水径流控制效果的影响[J]. 水电能源科学,2020,38(8):22-25.ZHANG W, HAO W W, YAN W B, et al. Influence of influent load on stormwater runoff control in grassed swales[J]. Water Resources and Power,2020,38(8):22-25. [8] 王龙涛, 赵建伟, 华玉妹, 等.表流型和渗滤型植草沟净化城市地表径流试验研究[J]. 环境科学与技术,2016,39(7):71-74.WANG L T, ZHAO J W, HUA Y M, et al. Study on infiltration grassed swale and surface flow grassed swale to purify urban surface runoff[J]. Environmental Science & Technology,2016,39(7):71-74. [9] 张潇月. 植被浅沟对城市雨水径流调控效能研究[D]. 邯郸: 河北工程大学, 2018. [10] 刘春晶, 李丹勋, 王兴奎.明渠均匀流的摩阻流速及流速分布[J]. 水利学报,2005,36(8):950-955. doi: 10.3321/j.issn:0559-9350.2005.08.010LIU C J, LI D X, WANG X K. Experimental study on friction velocity and velocity profile of open channel flow[J]. Journal of Hydraulic Engineering,2005,36(8):950-955. doi: 10.3321/j.issn:0559-9350.2005.08.010 [11] 赵振国, 黄春花.明渠均匀流研究[J]. 水利学报,2013,44(12):1482-1487. doi: 10.13243/j.cnki.slxb.2013.12.004ZHAO Z G, HUANG C H. Study on the uniform flow in open channel[J]. Journal of Hydraulic Engineering,2013,44(12):1482-1487. doi: 10.13243/j.cnki.slxb.2013.12.004 [12] 钟亮, 许光祥.曼宁公式分形细化初步研究[J]. 泥沙研究,2013(1):34-38. doi: 10.3969/j.issn.0468-155X.2013.01.006ZHONG L, XU G X. Preliminary study of fractal refinement of Manning's formula[J]. Journal of Sediment Research,2013(1):34-38. doi: 10.3969/j.issn.0468-155X.2013.01.006 [13] 夏旭. 集中进水植草沟沿程流量变化规律研究[D]. 北京: 北京建筑大学, 2021. [14] 住房和城乡建设部. 海绵城市建设技术指南: 低影响开发雨水系统构建[M]. 北京: 中国建筑工业出版社, 2015. [15] 贾界峰, 赵井卫, 陈客贤.曼宁公式及其误差分析[J]. 山西建筑,2010,36(7):313-314. doi: 10.3969/j.issn.1009-6825.2010.07.197JIA J F, ZHAO J W, CHEN K X. Manning's formula and error analysis[J]. Shanxi Architecture,2010,36(7):313-314. doi: 10.3969/j.issn.1009-6825.2010.07.197 [16] YE A Z, ZHOU Z, YOU J J, et al. Dynamic Manning's roughness coefficients for hydrological modelling in basins[J]. Hydrology Research,2018,49(5):1379-1395. doi: 10.2166/nh.2018.175 [17] YUSOF K W, MUHAMMAD M M, MUSTAFA R U M, et al. Analysis of Manning's and drag coefficients for flexible submerged vegetation[J]. IOP Conference Series: Materials Science and Engineering,2017,216:012046. doi: 10.1088/1757-899X/216/1/012046 [18] MAILAPALLI D R, RAGHUWANSHI N S, SINGH R, et al. Spatial and temporal variation of Manning's roughness coefficient in furrow irrigation[J]. Journal of Irrigation and Drainage Engineering,2008,134(2):185-192. doi: 10.1061/(ASCE)0733-9437(2008)134:2(185) [19] KAMALI P, EBRAHIMIAN H, PARSINEJAD M. Estimation of Manning roughness coefficient for vegetated furrows[J]. Irrigation Science,2018,36(6):339-348. doi: 10.1007/s00271-018-0593-9 [20] 朱钰, 石红鸽.生态边沟模型设计及水流特性试验研究[J]. 公路交通科技(应用技术版),2017,13(2):117-120. [21] 冯玉启, 王文海, 李俊奇, 等.植草沟专用堰的设计与率定研究[J]. 环境工程,2019,37(7):30-33.FENG Y Q, WANG W H, LI J Q, et al. Design and its calibration of special turtles for grassing ditch[J]. Environmental Engineering,2019,37(7):30-33. [22] COWAN W L. Estimating hydraulic roughness coefficients[J]. Agricultural Engineering,1956,37(7):473-475. [23] AL-SAFI H I J, SARUKKALIGE P R. The application of conceptual modelling to assess the impacts of future climate change on the hydrological response of the Harvey River Catchment[J]. Journal of Hydro-Environment Research,2020,28:22-33. doi: 10.1016/j.jher.2018.01.006 [24] MOHAMMED M H, ZWAIN H M, HASSAN W H. Modeling the impacts of climate change and flooding on sanitary sewage system using SWMM simulation: a case study[J]. Results in Engineering,2021,12:100307. doi: 10.1016/j.rineng.2021.100307 [25] 沈子欣, 阚丽艳, 车生泉.生态植草沟结构参数变化对降雨径流调蓄净化效应的影响[J]. 上海交通大学学报(农业科学版),2015,33(6):46-52.SHEN Z X, KAN L Y, CHE S Q. Effects of grass swales structure parameters on storage and pollutant removal of rainfall runoff[J]. Journal of Shanghai Jiao Tong University (Agricultural Science),2015,33(6):46-52. [26] ZHANG S T, LIU Y, WANG Z K, et al. Effects of slope and flow depth on the roughness coefficient of lodged vegetation[J]. Environmental Earth Sciences,2020,79(6):1-12. [27] ZHANG H Y, WANG Z Y, XU W G, et al. Determination of emergent vegetation effects on Manning's coefficient of gradually varied flow[J]. IEEE Access,2019,7:146778-146790. doi: 10.1109/ACCESS.2019.2946917 [28] KIRBY J T, DURRANS S R, PITT R, et al. Hydraulic resistance in grass swales designed for small flow conveyance[J]. Journal of Hydraulic Engineering,2005,131(1):65-68. ◇ doi: 10.1061/(ASCE)0733-9429(2005)131:1(65) -
下载:
点击查看大图
计量
- 文章访问数: 221
- HTML全文浏览量: 107
- PDF下载量: 17
- 被引次数: 0
