MARC软件在溢洪道预应力闸墩结构分析中的运用

糯扎渡水电站溢洪道最大泄量31318m3/s,为国内排名第一、世界第四;泄洪水头182m,泄洪功率55860MW,均为世界第一位。闸门控制段设置8孔15m×20m(宽×高)弧形闸门,闸墩厚4.5m,最大弧门推力达38510kN,设计采用预应力混凝土结构。在结构分析时,运用了MSC公司的MARC软件对闸门运行的各种工况进行了分析,得出了相应的结构应力成果。文章详细介绍了预应力闸墩有限元分析过程及应力计算成果。     

彭水水电站大尺寸弧门预应力闸墩设计

彭水水电站表孔工作弧门具有孔口尺寸大、水推力大等特点。为改善闸墩受力状态，确保泄洪消能安全，闸墩设计采用预应力锚固技术。介绍了彭水水电站表孔预应力闸墩的锚束布置、张拉力设计、锚固体系选择，运用三维有限元法比较了预应力闸墩和常规混凝土闸墩的应力分布及大小和钢筋布置。     

天生桥一级水电站闸墩预应力锚索施工

1　工程概况天生桥一级水电站位于广西、贵州交界的南盘江干流上,是红水河梯级开发水电站的第一级.该电站主要建筑物由混凝土面板堆石坝、开敞式溢洪道、放空隧洞、引水系统和地面厂房等主要建筑物组成.溢洪道布置在右岸垭口,系本电站惟一的泄洪建筑物,总长1745m,其中引渠长1215m,采用复式断面,底宽120m,引渠末端接溢流堰,溢流堰设5孔13m×20m的弧形闸门,采用异形挑流消能.2　锚索施工设计溢洪道溢流堰闸墩,为了平衡弧形闸门支铰的水推力,改善牛腿内和牛腿前方闸墩的应力状态,#1～#6闸墩在设计上采用了预应力结构.每个闸墩均布置有预应力主…     

糯扎渡新型预应力闸墩工作性态研究

糯扎渡水电站溢洪道最大泄量31318 m3/s,为国内排名第一、世界第四;泄洪水头182 m,泄洪功率55860 MW,均为世界第一位。闸室控制段共设8个15 m×20 m(宽×高)表孔,每孔均设检修门和弧形工作闸门,中墩厚4.5 m,最大弧门推力达38216 kN,设计采用预应力混凝土结构。文章采用ANSYS有限元软件对新型预应力闸门运行的各种工况进行了分析研究,得出了相应的结构变形和应力成果。     

大朝山水电站泄洪排砂底孔闸墩预应力锚索施工

大朝山水电站 1号、2号、3号泄洪排砂底孔弧形工作闸门单铰推力为 3 3× 10 4 kN ,闸室采用梁式预应力闸墩结构 ,弧门支臂传递的推力由支承大梁向边墩和中墩传递 ,从而减小了支承大梁的结构尺寸。文章概括叙述了泄洪排砂底孔闸墩预应力锚索设计及施工的基本情况     

构皮滩水电站大坝中孔闸墩U形无黏结预应力锚索施工

构皮滩水电站大坝泄洪中孔出口弧形工作闸门支承结构的预应力锚索主锚索首次采用分束管座U形无黏结预应力锚索,锚索安装穿过预埋在坝体内的护管,U形端采用分束管座形式,可以有效减少预应力损失。本文介绍了大坝泄洪中孔闸墩分束管座U形无黏结预应力锚索的施工特点及主要施工方法。     

水闸闸墩牛腿加固及混凝土防碳化处理

一、工程概述广东省江门市北街水闸枢纽由水闸和船闸两部分组成,水闸共5孔,其中右4孔为泄洪孔,每孔净宽为 12 m,闸底板高程-4 m,闸顶高程6．7 m,水闸闸室长 22 m。泄洪孔加固后采用弧形钢闸门控制,设胸墙,胸墙底高程1．5m。泄洪孔闸室采用分离式底板结构,底板厚 1．2 m,闸墩厚2．5 m,闸墩采用混凝土桩基础。原设计经计算因1976年施工时分洪孔的闸墩结构设计中只放置了水平、垂直向钢筋,没有放置足够的扇形受拉钢筋。此次施工原设计将牛腿拆除及闸墩侧壁全部拆除 20 cm,重新浇筑混凝土。后经中国水利水电科学研究院建议,拟采用粘贴碳纤维对闸墩牛腿进行补强加固处理,采用 SK_PCS涂层材料对闸墩混凝土进行防碳化及防渗处理。     

水电站泄洪底孔预应力闸墩锚索监测分析

通过介绍某水电站泄洪底孔预应力闸墩设计施工情况,及对闸墩预应力锚索监测资料进行分析,综合判断底孔预应力闸墩目前运行情况.     

水电站工作弧门预应力闸墩结构特性研究

水电站工作弧门预应力闸墩具有孔口尺寸大、水推力大等特点。为改善其受力状态，确保泄洪消能安全，设计通常采有预应力锚固技术。本文在简要介绍闸墩预应力锚索设计的基础上，运用三维有限元法对其位移及应力分布规律进行了研究。给出了预应力闸墩的几个主要受力特征。     

大花水水电站拱坝中孔闸墩裂缝成因分析及处理措施研究

针对大花水水电站中孔闸墩出现的裂缝,采用三维实景建模和表面波法等手段对缝隙分布情况进行检测,并通过泄洪振动监测缝隙开度变化。结合中孔闸墩裂隙现状,运用三维非线性有限元分析方法对缝隙成因、缝隙对大坝安全影响进行分析,并提出对缝隙的处理措施。结果表明:中孔闸墩裂缝是闸墩在复杂高应力状况下引起的温度裂隙;裂隙在采用化学灌浆处理后,不影响大坝整体安全,大坝处于安全状态。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

Impacts of Microcystis on algal biodiversity and use of new technology to remove Microcystis and dissolved nutrients

Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L^?1 PO₄. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

簸箕李引黄灌区水沙分布及优化调度的经验

灌区利用水沙观测所取得的资料和试验数据，运用水沙运动力学理论，总结分析和揭示了灌区水沙分布的规律和特点。在此基础上，结合灌区的实际运行情况，围绕减少骨干渠道的淤积进行探讨、研究，进而，优化水沙调度方案。该方案实施后，骨干渠道减旅伴效果明显，取得了成功的经验。     

小湾水库大坝防渗面板及其裂缝的加固处理

小湾水库大坝防渗面板整体抗渗性能差,且存在多条裂缝,通过对面板钢丝网喷涂丙乳砂浆加固处理及其裂缝修补,大坝渗漏量明显减少,且左岸上灌浆廊道内及大坝下游坝面92～93 m高程下廊道入口处原有小股射流全部消失.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.