沙沙坡水电站溢流堰面抗冲磨混凝土施工

堰面混凝土施工为溢流坝混凝土施工难点部位之一,容易产生麻面、错台、变形、露筋及裂缝等混凝土质量通病.沙沙坡水电站工程溢流堰面抗冲磨混凝土施工采用特制的堰面轻型桁架,使模板安拆与混凝土浇筑平行作业,并通过优化施工方案加快施工进度,防止骨料入仓分离,加强混凝土表面抹光修整工艺,使溢流堰面抗冲磨混凝土施工质量优良.     

浅谈朱庄水库除险加固工程溢流堰面施工技术

本文介绍了朱庄水库除险加固工程中原溢流堰面拆除、溢流堰面植筋、轨道模板浇筑等施工方法,对其他水库除险加固工程的施工具有一定的借鉴作用。     

盘道水库溢流堰混凝土施工技术

盘道水库溢流堰为WES曲线堰面,施工历时长,施工工序复杂.文章介绍了盘道水库溢流堰的模板设计、混凝土浇筑等方面的施工技术,可为类似工程施工提供参考借鉴.     

盘道水库溢流堰混凝土施工技术

盘道水库溢流堰为WES曲线堰面,施工历时长,施工工序复杂.文章介绍了盘道水库溢流堰的模板设计、混凝土浇筑等方面的施工技术,可为类似工程施工提供参考借鉴.     

溢流堰曲线堰面模板施工技术在工程中的应用

为保证水利工程水流顺畅,一般溢流堰面由曲线段+直线段+弧线段组成,使堰面成为高速过水面,直接影响使用功能和外观质量。通过在堰体规定的位置测设模板承托装置位置,预埋锚栓,作为堰体面层钢筋支架的定位点,同时采用三点固定法,在模板承托装置处安装钢筋支架,结合模板缝位置布置,与事先预埋的锚栓焊接,最后根据设计图纸堰面制作、安装、混凝土浇筑、养护、拆模等操作的施工方法,确保溢流堰坝曲线堰面的混凝土外观质量。     

混凝土倒模法施工技术

某水库正常溢洪道重建工程要求汛前完成混凝土堰面施工,由于工期紧迫,必须采取适宜的施工方法才能满足要求。施工时通过对滑模法、人工抹面法、倒模法3种堰面混凝土施工方案进行比选,最后确定采用倒模法。采用倒模法浇筑堰面,能够保证堰面的表面平滑,混凝土内部密实度,同时加快了施工速度,保证了工期。     

底孔溢流堰设计与施工的几个关键技术探讨

本文探讨了浯溪口水利枢纽工程底孔溢流堰设计与施工中所采取几个的关键技术;其中基于物理模型试验进行底孔溢流堰设计。模型试验结果表明底孔溢流堰设计既能保证水流平顺,过流能力大,又能保证不出现导致堰面发生破坏的堰面负压。此外,底孔溢流堰施工通过采用倒弧面模板和混凝土分区等工程措施可保证堰体混凝土满足强度、抗冲、温控以及平整度等要求。这些技术可为类似工程溢流堰设计与施工提供重要参考。     

溢流堰堰面滑模施工简介

设计溢流堰堰面时,为了追求水流阻力小和线形美观,一般设计成流线型曲面,同时溢流堰堰面要有平滑、高强等防冲耐磨的特点,这给施工提出了较高要求.为了保证施工质量,实现设计意图,较好的方法是采用滑动模板进行堰面混凝土施工.     

麦洛维大坝溢流坝堰面滑模施工研究

苏丹麦洛维大坝溢流坝堰体混凝土施工是在梳齿导流期间上、下游堰孔关闭下进行的，分为堰体台阶混凝土浇筑和堰面混凝土浇筑。由于堰面外形多变、陡、高、长，施工难度较大，经过多方面的认真研究，制定了周全、详细的施工方案，现场施工也安排得恰当、合理，最终使用有轨滑模施工方式圆满完成了8号堰面的浇筑。     

顶部建橡胶坝的溢流堰体型研究

溢流堰整体水工模型试验显示，水流通过堰面时，与堰面分离，形成大面积低压气囊，堰面负压严重，水流流态不稳定。通过试验观测与研究，分析了问题产生的原因，经过调整堰顶平台与下游堰面连接段的体型，分别采用WES型曲面连接段及较大半径的圆弧曲面连接段，均消除了堰面低压气囊，降低了堰面真空度，改善了流态。两种修改方案相比，以WES型曲面连接段方案为优。     

NUMERICAL INVESTIGATION OF FLOW OVER A WEIR

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＷｅｉｒｉｓｔｈｅｃｏｎｓｔｒｕｃｔｉｏｎｗｉｄｅｌｙｕｓｅｄｉｎｈｙｄｒａｕｌｉｃｅｎ ｇｉｎｅｅｒｉｎｇ.Ｉｔｉｓｖｅｒｙｉｍｐｏｒｔａｎｔｔｏｉｎｖｅｓｔｉｇａｔｅｔｈｅｂｅｈａｖｉｏｒｏｆｔｈｅｆｌｏｗｓｏｖｅｒａｗｅｉ     

ENVIRONMENTAL GRADIENTS ALONG A LOWLAND WEIR POOL IN THE SOUTHERN MURRAY‐DARLING BASIN,AUSTRALIA

The 60‐km‐long pool created by the Mildura weir exhibits pronounced physical, chemical and biological gradients along its length. As the river deepens and widens downstream along the weir pool, the flow velocity decreases and the potential for thermal stratification (intensity and duration of stratification) increases. Most nutrient concentrations (TN, NO_x, FRP) as well as the euphotic depth increased in the downstream direction whereas TP and turbidity decreased. The increase in bioavailable nutrients co‐occurred with an increase in electrical conductivity suggesting the presence of relatively more saline groundwater inflows to the weir pool. Throughout the summer (12 December 2003–18 March 2004), with the exception of 8 days, the water column throughout the weir pool mixed completely on a diurnal basis in the deeper sections and was continuously mixed in the shallower upstream sections. This mixing substantially reduced the mean irradiance experienced by the phytoplankton near the weir. Maximum cyanobacteria concentrations were observed in the mid‐weir pool where the range of conditions was most suitable. Diatom abundance increased along the most downstream 20 km of the pool where the water column was deeper and slower flowing yet still mixed completely on a diurnal basis. Peaks in cyanobacteria biomass are not expected in the lower weir pool until lower discharges promote persistent thermal stratification and increase the mean irradiance in the surface mixed layer. Copyright © 2011 John Wiley & Sons, Ltd.     

WEIR POOL SURCHARGE AND A CORRESPONDING INCREASE IN ALGAL BIOFILM COMMUNITY DIVERSITY IN THE LOWER RIVER MURRAY,SOUTH AUSTRALIA

Lowland rivers impounded by weirs are often operated to provide stable water levels. In the lower River Murray, stable water levels promote algal biofilms dominated by stalked diatoms, filamentous green algae and Cyanobacteria. In summer 2005–2006, the Lock 5 weir pool was surcharged for environmental benefit. Algal biofilms grown on artificial substrates were compared to the following year when the water level remained stable. On both occasions, substrates were fixed at 300‐mm depth in the river channel and a connected wetland. During the surcharge, additional floating substrates were deployed to control for the change in water level. The algal communities that developed during both years were dominated by diatoms. A greater diversity in the biofilm community was evident during the 4‐month surcharge when compared with the following year. This was due to a much greater change in algal biofilm community composition over the 4 months of the surcharge, compared with biofilms grown during a period of stable water level, when the community changed little after 1 month. The lack of difference between fixed and floating substrates suggests that the change in water level was not responsible for the difference between the surcharge and stable level biofilms. Possible reasons for the difference between years include light, nutrients and water temperature. Although the effect of the surcharge could not be definitively defined, these results provide some evidence that weir pool surcharge may be used to improve algal biofilm diversity when compared with the current stable water level regime. Copyright © 2011 John Wiley & Sons, Ltd.     

THE RE-DERIVATION OF THE VORTICITY EQUATION OF THE LAYERED FLOW OF THE SHALLOW SEA

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＦｏｒｔｈｅｌａｒｇｅ ｓｃａｌｅｏｃｅａｎｉｃｆｌｏｗ ,ｐｅｏｐｌｅｕｓｕａｌｌｙｓｅｅｋｔｈｅｓｏｌｕｔｉｏｎｓｆｒｏｍｔｈｅｑｕａｓｉ ｇｅｏｓｔｒｏｐｈｉｃｖｏｒｔｉｃｉ ｔｙｅｑｕａｔｉｏｎｄｅｒｉｖｅｄｆｒｏｍｔｈｅｐｅｒｔｕｒｂａｔｉｏｎｂｙｕｓｉｎｇＲｏｓｓｂｙｎｕｍｂｅｒεａｓａｌｉｔｔｌｅｐａｒａｍｅｔｅｒ.Ａｎｉｍｐｏｒｔａｎｔａｐｐｒｏｘｉｍａｔｉｏｎｗｈｅｎｄｅｄｕｃｔｉｎｇｖｏｒｔｉｃｉｔｙｅｑｕａｔｉｏｎｉｎｔｈｅｌａｙｅｒｅｄｓｅａｗａｔ…     

梯形断面渠道中水跃共轭水深计算

提出先由经验公式计算梯形断面渠道中水跃共轭水深的初值，然后由相应的公式计算出准确的共轭水深的方法。     

周宁大坝上游面裂缝处理

针对福建省周宁碾压混凝土坝在施工过程中坝体所产生的裂缝,采取了相应的处理措施．处理后运行效果良好．     

章江洪水特点与防洪对策

通过分析章江洪水特点和防洪存在的主要问题,提出了章江防洪的主要对策和措施.     

浅析真空断路器的操作过电压的机理及抑制措施

详细分析了真空断路器操作过电压的机理,并介绍了抑制操作过电压的主要措施.     

吉安市山洪灾害及其雨水情自动监测系统现状与要求

介绍了吉安市流域情况、历史山洪灾害情况和特点,以及山洪灾害雨水情监测现状;最后就雨水情自动监测系统的要求作了阐述.     

飞剑潭水库大坝防渗加固工程施工

介绍飞剑潭水库大坝防渗加固工程的处理方案、设计参数、施工方法，及特殊情况处理措施和施工质量控制方法。