排序方式: 共有39条查询结果,搜索用时 31 毫秒
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为体现HEC-RAS模型中感潮河段上桥梁壅水变化,建立了一维非恒定流数学模型,计算了2002年3月长江苏通大桥的壅水情况。并进一步介绍和比较了铁路工程水文勘测设计规范公式以及HEC-RAS内设的能量法、动量法、Yarnell法计算公式,对公式计算结果与HEC-RAS相关经验系数等设置进行了探讨。最后将各公式应用于3月份的苏通大桥壅水计算,结果发现:HEC-RAS的能量法和Yarnell法较符合规范法,适用于计算感潮河段的非溢流桥梁壅水;而动量法则与实际数值偏差较大,不适合该地区应用。同时比较了HEC-RAS的3种方法对扩缩系数、经验系数以及无效区域的敏感性,结果表明:扩缩系数对能量法影响最大,Yarnell法依赖于经验系数,动量法与无效区域有关,但其具体设置需要更详细的资料进行研究。研究成果可为非恒定流桥梁壅水数值模拟方法提供一些参考。 相似文献
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运用HEC-RAS软件构建珠江三角洲一维河网非稳定流水动力模型,利用该模型与侧向水工结构溃坝模块(Lateral Structure Breach),进行湖涌停车场所在佛山市罗格围的溃堤模拟计算。得到不同溃口宽度、溃口修复时间等条件下溃口处的流量过程、外江水位过程、围内水位过程。实例结果表明,溃口宽度是影响围内设计水位的重要因素,当溃口宽度达某一值时,围内设计水位将趋于稳定。基于HEC-RAS的溃堤模型可与当地防汛抢险相结合进行溃堤影响分析,可为珠江三角洲堤围内停车场设计提供可靠的技术支持,供借鉴。 相似文献
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为准确模拟大坝失事后溃坝洪水的下游演进,运用HEC-RAS二维水动力学模型,修正面板坝溃口发展曲线,设计两种闸门开度的小井沟面板坝漫顶溃坝工况,模拟水库泄洪影响下溃坝洪水的下游演进并生成相应的洪水风险图、最大流速分布图、滞留时间图。研究结果展现了溃坝洪水在中下游平原丘陵地区的泛滥情况、洪水风险的分布差异以及水库泄洪对溃坝洪水的影响。分析得出不同闸门开度下溃坝洪水在中下游平原丘陵地区的淹没水深和范围差异明显,最大流速和洪水滞留时间区别不大, 说明水库全力泄洪能有效降低溃坝洪水对下游人员聚居的平原地区的危害。研究成果对后续的人员疏散和损失估计具有重要参考意义。 相似文献
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为深入研究万家寨水库上游河段冰期的冰情特征与演变规律,并为该河段的防凌减灾工作提供科学依据,依据实测的水位、流量、河道地形资料,通过HEC-RAS软件建立黄河干流万家寨水库上游坝址至头道拐段的水动力模型,模拟研究河段2013年4月—2014年3月的水动力变化过程,探究各典型时期水动力参数的时空分布特性。结果表明:(1)基于实测水位数据对模拟结果进行对比验证,模拟水位与实测水位的相对误差13%,吻合度较高,可以较好地模拟研究河段的水力要素随时间、空间的演变过程。(2)研究区域枯水期、汛期、流凌期、开河期模拟水位空间分布存在差异性。结合流量特征分析,各典型时期上下游河段的水位差与流量呈正相关关系。(3)通过分析各典型断面处的水深和流速变化过程,曹家湾河段在冰期易卡冰结坝、诱发冰凌灾害的主要原因为:该河段过水断面相对较小且水流经过此处流速明显降低。 相似文献
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R. Kiyengo M. Majaliwa R. Twinomuhangi H. Waswa 《The International journal of environmental studies》2020,77(3):480-491
ABSTRACT This study was conducted to establish the spatio-temporal distribution of flash floods and to learn why people prefer to settle in flood-prone areas of Lubiji micro-catchment in Kampala City. Rainfall data were analysed to ascertain Peak Runoff expected for the given flood event based on Soil Conservation Service Curve Numbers. The micro-catchment was delineated in the Arc GIS 10.0 programme, from the Digital Elevation Model. Feature classes were created to obtain the reach extents and river banks. HEC-RAS model was then used to create flood inundation maps in Arc GIS 10.0 between 1983 and 2014. High magnitude flash floods occurred almost after every three years and the spatial extent varied from 4.4 to 6.8 km2. The choice of settlement location in flood-prone areas was influenced by socio-economic ties. The flood hazard maps produced will aid land-use planning, resettlement of the people and setting up a flood forecasting system. 相似文献
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Urban flooding in Chittagong City usually occurs during the monsoon season and a rainwater harvesting(RWH) system can be used as a remedial measure. This study examines the feasibility of rain barrel RWH system at a distributed scale within an urbanized area located in the northwestern part of Chittagong City that experiences flash flooding on a regular basis. For flood modeling, the storm water management model(SWMM) was employed with rain barrel low-impact development(LID) as a flood reduction measure. The Hydrologic Engineering Center's River Analysis System(HEC-RAS) inundation model was coupled with SWMM to observe the detailed and spatial extent of flood reduction.Compared to SWMM simulated floods, the simulated inundation depth using remote sensing data and the HEC-RAS showed a reasonable match,i.e., the correlation coefficients were found to be 0.70 and 0.98, respectively. Finally, using LID, i.e., RWH, a reduction of 28.66% could be achieved for reducing flood extent. Moreover, the study showed that 10%e60% imperviousness of the subcatchment area can yield a monthly RWH potential of 0.04 e0.45 m~3 from a square meter of rooftop area. The model can be used for necessary decision making for flood reduction and to establish a distributed RWH system in the study area. 相似文献