【作者】 王丽；

【导师】 金鹏康；

【作者基本信息】 西安建筑科技大学 ， 建筑与土木工程， 2021， 硕士

【摘要】 近年来,随着低影响开发(Low Impact Development,LID)措施研究的不断推进以及城市排水防涝管理工作的逐步完善,我国城市洪涝现象已有所缓解,但因强降雨导致的住宅小区内涝事件仍时有发生。对此,本文在充分解析某住宅小区现状排水防涝系统特征的基础上,通过构建暴雨洪水管理模型(Storm Water Management Model,SWMM),开展了易涝点的精准识别以及住宅小区排水防涝设计方案优化与效果评价。研究结果对于提升住宅小区排水防涝能力具有一定的理论与实践意义。论文通过分析研究区域内的短历时强降雨事件,采用SWMM模型探究了不同重现期下小区现状雨水系统的排水能力。结果表明,当降雨量为50.89mm(10年一遇)时,溢流汇水节点溢流时间均小于15min,其后端雨水收集管道进流量在其承载能力范围内,对应区域短时积水可以及时排出,小区内部未出现内涝现象;当降雨量增大至62.95mm(20年一遇)时,溢流时间超过15min的汇水节点开始出现,其后端雨水收集管道进流量超过其承载能力(即出现管道超载现象),对应区域积水严重,内涝风险显著升高;当降雨量进一步增大至77.37mm(50年一遇)时,已超出小区雨水管道设计排水能力,溢流节点与超载管段占比大幅升高,小区内涝现象进一步加剧。基于上述研究,提出了住宅小区易涝点的判断条件,并结合不同重现期下小区各汇水节点溢流和管渠满载情况分析,探明了易涝点类别及其产生的原因。结果表明,在设计重现期为20a的条件下,以汇水节点溢流时间是否超过15min为判定原则,确定小区内共存在9个易涝点,主要分布在管道汇接点(J5、J16、J21、J22)、雨水收集管网末端(J4)和地面透水率较低区域(J24、J25、J26、J27)。分析原因,管段汇接点与末端节点转输上游子汇水区雨水量较大,导致其排水任务过重;而地面透水率较低区域的下渗量低,引发其所在子汇水区地表径流量大幅度升高,增加了内涝风险。针对研究区域下垫面条件及空间场地需求等特征因素,筛选透水铺装、生物滞留设施和雨水储存设施对易涝点进行LID改造,并分析了改造后小区的实际排水能力。改造后,在实际降雨量为56.5mm时,小区内未出现溢流节点与积水现象。当实际降雨量升高至68.5mm时,小区综合径流系数由改造前的0.85降低至0.48,溢流节点数量下降至2个,溢流节点削减率为94%,且最大溢流时间仅为4min。改造后未出现重现期为50年的降雨,故采用SWMM模型对该条件下的管网排水能力进行模拟,结果显示节点最大溢流时间为12min。综上可知,对小区进行易涝点LID改造可有效改善节点溢流情况,显著提升小区排水防涝能力,为住宅小区的合理海绵化改造提供了借鉴。更多还原

【Abstract】 In recent years,with the continuous advancement of research on low impact development(LID)measures and the gradual improvement of urban drainage and waterlogging prevention management,urban waterlogging in China has been alleviated,but waterlogging events in residential areas caused by heavy rainfall still occur from time to time.In this regard,on the basis of fully analyzing the characteristics of the current drainage and waterlogging prevention system in a residential area,through the construction of storm water management model(SWMM),the accurate identification of waterlogging points and the optimization and effect evaluation of drainage and waterlogging prevention design scheme in residential areas are carried out.The research results have certain theoretical and practical significance for improving the drainage and waterlogging prevention ability of residential areas.By analyzing the short-duration heavy rainfall events in the study area,the SWMM model is used to explore the drainage capacity of the current rainwater system in the residential area under different return periods.The results show that when the rainfall is50.89 mm(once in 10 years),the overflow time of the overflow catchment node is less than 15 min,and the inflow of the back-end rainwater collection pipeline is within the range of its carrying capacity.The short-term accumulated water in the corresponding area can be discharged in time,and there is no waterlogging in the community.When the rainfall increased to 62.95 mm(once in 20 years),the catchment node with overflow time more than 15 min began to appear,and the inflow of the rear rainwater collection pipeline exceeded its carrying capacity(pipeline overload phenomenon).The corresponding area had serious water accumulation,and the waterlogging risk increased significantly.When the rainfall further increased to 77.37 mm(once in 50 years),it exceeded the design drainage capacity of the rainwater pipe in the residential area.The proportion of overflow nodes and overload pipes increased significantly,and the waterlogging phenomenon in the residential area further intensified.Based on the above research,the judgment conditions of waterlogging points in residential areas are proposed,and the types of waterlogging points and their causes are verified by analyzing the overflow of each catchment node and the full load of pipe and canal under different return periods.The results show that under the condition of the design return period of 20 a,taking whether the overflow time of the catchment node exceeds 15 min as the judgment principle,there are 9 waterlogging-prone points in the area,which are mainly distributed at the junction of the pipeline(J5,J16,J21,J22),the end of the rainwater collection pipe network(J4)and the low ground permeability areas(J24,J25,J26,J27).Analysis of the reasons,the connection point of the pipe section and the end node transfer upstream sub catchment area rainfall is large,resulting in excessive drainage tasks.The low infiltration in the area with low surface permeability leads to a significant increase in surface runoff and increases the risk of waterlogging.According to the characteristics of the underlying surface conditions and space site requirements in the study area,the permeable pavement,biological detention facilities and rainwater storage facilities were selected to carry out LID reconstruction of the vulnerable points,and the actual drainage capacity of the transformed residential area was analyzed.After modification,when the actual rainfall is 56.5 mm,there is no overflow node and water accumulation in the area.When the actual rainfall increased to 68.5 mm,the comprehensive runoff coefficient decreased from 0.85 to 0.48,and the number of overflow nodes decreased to 2.The reduction rate of overflow nodes was 94%,and the maximum overflow time was only 4 min.There is no rainfall with a return period of 50 years after the reconstruction,so the SWMM model is used to simulate the drainage capacity of the pipe network under this condition.The results show that the maximum overflow time of the node is 12 min.In conclusion,the LID reconstruction of waterlogging-prone points in residential areas can effectively improve the node overflow,significantly improve the drainage and waterlogging prevention ability of residential areas,and provide reference for the reasonable sponge transformation of residential areas.更多还原