新疆阿勒泰地区水库溢洪道台阶式泄槽设计与应用

台阶式泄槽溢洪道的显著特点是沿溢流面的消能率大大提高,从而可免除或极大地缩短溢洪道末端所需消能工的尺寸。近几年来,阿勒泰地区将台阶式泄槽溢洪道运用于中小型水库、水闸中,运行工况很好。为此,作为一种优越消能形式,台阶式泄槽消能受到了水利工程行业广泛关注。本文结合阿勒泰地区富蕴县境内的莫勒达拜水库工程,对其溢洪道台阶式泄槽的设计予以研究,为以后相关工程项目的设计提供参考。     

台阶式溢洪道消能率影响因素分析

台阶式溢洪道利用台阶改变水流方向,导致水流动能耗散,对提高溢洪道消能效果具有重要意义。与光滑溢洪道相比,台阶式溢洪道的消能率更高,因此在水利工程中得到广泛应用。台阶式溢洪道消能效果主要用消能率衡量,与光滑溢洪道比,台阶式溢洪道的水力参数更加复杂。采用室内试验与理论分析耦合方法,分析了台阶式溢洪道台阶高度、流量、坡度对消能率的影响。研究表明:其它参数相同时,台阶式溢洪道长度增加,消能率增加;单宽流量增加,消能率减小;台阶高度增加,消能率增加。     

基于SPH的台阶式溢洪道最优消能率参数研究

为研究台阶式溢洪道的消能规律,明确台阶式溢洪道的最优消能率参数,利用DualSPHysics对台阶式溢洪道水流特征进行模拟,并通过与典型案例的对比分析验证了SPH方法对台阶式溢洪道水流模拟的适用性与准确性,模拟结果表明SPH方法可以较好地模拟台阶式溢洪道上的水流特征。通过建立不同单宽流量、台阶段坡度和台阶数目的共计288种工况对台阶式溢洪道消能规律及其影响因素进行了研究。结果表明：在其他条件一定的情况下,台阶式溢洪道的消能率与单宽流量呈负相关关系;台阶数目对台阶式溢洪道消能率的影响并不显著,但是存在一个台阶数目能使台阶式溢洪道的消能率达到最大值,该最优消能率对应的台阶数目在78~81阶范围内,此结论对指导实际工程应用有一定的参考价值。     

台阶式溢洪道的消能及其应用价值的探讨

作者总结了溢洪道消能率的计算公式、消能率的影响因素、台阶式溢洪道的适用范围;对某水库的台阶式溢洪道和光滑面溢洪道的两个方案在消能效果、消力池长度等方面进行比较,分析了这两种方案各自的特点。结果表明,台阶式溢洪道消能主要集中在台阶段,而且相对于光滑面溢洪道,大大缩短了消力池的长度,降低了投资。     

台阶溢洪道无因次消能水头规律与水面线计算

台阶式溢洪道消能水头是重要的水力参数,直接反映了台阶式溢洪道的消能情况。对台阶式溢洪道的消能水头及影响因素进行因次分析,引入相对临界水深、相对位置。通过对5组不同坡度,3个台阶高度,3个单宽流量共45个组合工况下的台阶式溢洪道进行模型试验研究,探讨无因次消能水头与相对临界水深、相对位置、坡度的关系。结果表明:无因次消能水头与相对位置呈现良好的线性关系;直线斜率与坡度呈线性递增关系,与相对临界水深无关。依据这些规律计算台阶式溢洪道沿程水面线,为台阶式溢洪道复杂水力特性计算提供了新方法。     

浅谈台阶式溢洪道的应用原理及应用前景

本文分别对梯阶式溢洪道的发展现状、消能原理、水流流态、消能效率及适用工程等方面的研究成果做了归纳与总结,提出了台阶式溢洪道在中小型水库中的运用优势.但是鉴于其研究的不统一性,台阶式溢洪道的应用还有待于今后更深入的研究.     

不同体型台阶溢洪道水流比能特性研究

台阶式溢洪道作为一种具备消能效果的泄水建筑物被广泛应用于碾压式混凝土重力坝建设过程中,但由于其消能效果研究的复杂性和现场试验的不可操作性,针对台阶式溢洪道消能效果研究从未间断。本文利用断面比能为研究参数,对不同台阶高度、不同单宽流量台阶式溢洪道消能效果进行了系统的研究。研究得出:在台阶式溢洪道泄水过程中,总水头随着泄水流程增加呈线性降低;水流断面比能在泄水过程中呈现先增加后逐渐趋于稳定的趋势,且断面比能稳定的流程临界值为35—40m;断面比能随着单宽流量的增加而逐渐增加,二者之间呈现正相关关系;台阶式溢洪道台阶高度越高,消能效果越明显,当台阶高度由0.5m增加至2m时,台阶式溢洪道消能效果提高18.3%。     

台阶式溢洪道的水力特性

台阶式溢洪道是水利工程中常见的新型泄洪消能方式之一,相比于其他消能方式有较高的消能率、能很好地降低溢洪道末端流速,工程造价低、不易发生空蚀等诸多优点。文章概述了台阶式消能工机理及其主要研究方法,归纳了学者对台阶式消能已有的研究结果,并从溢洪道表面台阶设置、水力特性参数、台阶自身形态与消能特性关系3个方面总结了消能率的影响因素,进一步讨论了"M"和"V"2种新型的台阶溢洪道消能特性,通过改变台阶形态增强了消能效果,较大程度地缩减了溢洪道的长度,降低了对下游消能设施的要求。     

台阶式溢洪道的消能及其应用价值的探讨

文中总结了溢洪道消能率的计算公式、消能率的影响因素、台阶式溢洪道的适用范围；对某水库的台阶式溢洪道和光滑面溢洪道的两个方案在效能效果、消力池长度等方面进行比较，分析了这两种方案各自的特点。结果表明，台阶式溢洪道消能主要集中在台阶段，而且相对于光滑面溢洪道，大大缩短了消力池的长度，降低了投资。     

某水库溢洪道除险加固工程方案比选试验研究

某水库溢洪道在泄洪过程中出现险情,需进行除险加固处理。基于模型试验,研究水库溢洪道除险加固方案中增大溢洪道泄槽底坡除险加固方案和台阶式溢洪道除险加固方案,对方案中水流流态、消能率等水力特性进行分析。试验结果表明,采用台阶式溢洪道满足溢洪道泄洪能力要求,大大提高了消能率,并且改善了溢洪道内水流流态,最终选定台阶式溢洪道消能方案作为水库溢洪道除险加固方案     

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.     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

浅谈优化Vray渲染在制作三维场景的应用研究

用Vray三维渲染引擎来渲染三维场景,其质量和速度是由一些影响因素和参数设置决定的,不同的参数和因素,可以得出不同的三维渲染效果.因此,分析、优化三维渲染质量和速度的影响因素,正确、合理的选择参数对提高Vray最后渲染阶段的质量和速度非常重要.     

固结、渗流和沉积控制方程研究

本文从两相流体动力学的守恒方程出发，考虑固相、液相的相对运动，推导了可以考虑场的不均匀性和流体压缩性的统一形式的控制方程，并对方程所基于的物理概念和相互联系进行了必要的分析。通过对方程适当形式的表达，可导出用于大、小变形固结、渗流和沉积的简化方程，显示了在不同领域的三个理论存在一定的统一性。方程推导过程并未对本构关系加以限制，适用范围较广。依据实际问题的要求，作了不同形式的简化。     

四川省及重庆市中型水电站效益分析

该文分析了四川省及重庆市几座中型水电站的调查材料表明：四川省及重庆市中型水电站不仅在川渝主网和地方电网中起着很大的作用，并具有巨大的社会效益，同时还有综合利用效益，说明修建中型水电站的优越性．     

Site modelling methods for detecting hydrologic alteration of flood frequency and flood duration in the floodplain below the carlyle dam,lower Kaskaskia River,Illinois, USA

Reports concerning the influence of dams on river hydrology vary among researchers, interest groups and government agencies. These often contradicting statements may occur because changes in hydrology caused by dams are distinct for each dam and river watershed. The objective of this research was to use site specific techniques to determine if the 1967 installation of the Carlyle Dam, lower Kaskaskia River, Illinois, altered flood frequency and duration within the forested floodplain located below the dam. Results indicated a decrease in flood duration and frequency, and a decrease in annual flood frequency variation at a site 6.4 km below the dam. Pre‐dam versus post‐dam differences in flood frequency and duration at the site 32.2 km below the dam were related to climate rather than dam effects. Although dam impacts are a concern, this research shows that distance downstream from the dam and downstream tributary and watershed characteristics should be considered before assuming that the dam has changed hydrologic parameters for portions of rivers. This research also indicates that areas of the lower Kaskaskia River may still maintain hydrologic ecological integrity, and could be targeted for restoration and adaptive management purposes. Hydrologic modelling combined with river gage and on‐site well measurement techniques presented in this study could provide detailed flood frequency and duration information for land use, sociological and geomorphological questions in focus areas within river floodplains. Copyright © 2008 John Wiley & Sons, Ltd.     

Statistical tools for thermal regime characterization at segment river scale: Case study of the Ste‐Marguerite River

Suitable thermal fish habitats are constrained by both maximum and minimum temperature tolerances. A multivariate and geostatistical approach was developed to estimate stream thermal characteristics at the river segment scale. Data from 22 temperature‐monitoring stations during summer 2007 were used to estimate monthly maximum temperature as well as thermal characteristics such as the number of events, the cumulative degree–days and the associated duration over specific temperature thresholds of 19 and 21°C. The probability of exceeding these temperature thresholds has also been interpolated. The methodology relies on the construction of a multivariate space using physiographic and hydrological characteristics of gauging stations as inputs in a canonical correlation analysis (CCA). A geostatistical interpolation technique, ordinary kriging, was subsequently used to perform interpolation in the physiographical space constructed using CCA. Results from this study were obtained for thermal characteristics estimated into two different interpolation spaces: (1) a 7 metrics space, and (2) an 8 metrics space. Cross‐validation technique has been performed and satisfactory results were obtained. Kriging thermal characteristics (magnitude and duration) into the 7 metric space for a 19°C threshold exceedance leads to best results with Relative Root Mean Square Error (RRMSE) ranging between 9.66 and 15.08%. The study shows that kriging in a multivariate space is a promising tool for water resources managers, especially in cases where risk mapping for lethal or sub‐lethal temperature thresholds may be required for a specific fish species. Copyright © 2010 John Wiley & Sons, Ltd.     

掺MgO混凝土的宏细观试验研究

利用MgO膨胀剂的延迟微膨胀效应能显著提高大体积混凝土的力学性能,产生的预压应力还能有效提高大体积混凝土抵抗温度开裂的能力,但目前对其微观机理研究不多。采用宏观与微观相结合的方式,研究了不同活性指数、不同掺量的MgO混凝土的力学性能,利用SEM/EDS微观分析手段揭示了MgO对混凝土性能影响的作用机理。试验结果表明：MgO取代部分水泥掺入混凝土中,混凝土的力学性能降低;掺量为4%~5%时,活性指数为100s的MgO混凝土的膨胀率大于活性指数为50 s的MgO混凝土;MgO混凝土的膨胀特性与Ca,Si,Mg,Al等元素的分布情况有关,掺入的MgO将改变界面区Ca,Si,Mg元素的富集特性,Ca元素和Mg元素更易于在界面区富集,导致混凝土宏观力学性能的降低。     

基于MIDAS软件探讨施工工序对深基坑稳定性的影响

基于武汉地铁名都站深基坑工程与水文地质勘察资料,建立了三维工程地质仿真计算模型。依据名都站深基坑开挖支护方案,利用有限元软件MIDAS的摩尔-库仑本构模型,对武汉地铁名都站深基坑施工过程中,不同施工工序下每步开挖之后,基坑的变形情况做仿真模拟计算,并对比分析其对基坑稳定性的影响。结果表明：基坑围护结构的变形情况与施工工序有很大的关系,施工工序越合理,上部土体变形越小,反之越大。因此,在基坑工程的施工过程中,要注重施工步骤的划分与合理安排,从而保证基坑工程的安全。研究成果为以后武汉地区基坑工程的施工设计提供了值得借鉴的经验。