桓仁水电站24号坝段稳定性分析

桓仁水电站24号坝段基础为透水性较弱的11岩层,其下为透水性强的12岩层,12岩层在24号坝段埋藏较浅。坝基帷幕在12岩层未封闭,承压水从24号坝段下游F1断层切割处出来,对24号坝段连同11岩层稳定不利。实测资料显示,24号坝段12岩层地下水位偏高且部分测孔水位有增大趋势。经分析,该坝段变形稳定,坝基扬压力无明显趋势性变化,坝基渗压系数在设计允许范围内,且该坝段基础无深层滑动面,因此24号坝段不存在稳定问题。     

新安江大坝岸坡坝段扬压力偏高成因及其影响

在对新安江水电站坝基扬压力观测资料进行了分析时发现，一些坝段坝基扬压力偏高，为了保证大坝的安全，采用变化规律分析，统计模型分析和综合成因分析等方法，对坝基扬压力偏高的成因进行了分析，认为影响坝坡3、20、22、23号坝段坝基扬压力的主要因素是上游库水位；其次是基岩温度和降水。结果表明，岸坡坝段强度满足规范要求，坝基面未出现拉应力。建议对排水孔进行全面检查和疏通，并有针对性地采取工程加固措施；对3号坝段加强监测和分析。     

三峡工程1～5号机组厂房坝段坝基地质问题专题通过专家审查

三峡工程１～５号机组厂房坝段坝基地质问题专题通过专家审查６月中旬，三峡工程１～５号机组厂房坝段坝基地质专题通过专家审查。至此，先后勘察研究了近２０年的本坝段坝基深层抗滑稳定的关键问题——缓倾角结构面及抗滑稳定条件终于得出了科学的结论，为该项目的技术设...     

莫若嘎哈堪达水电站碾压混凝土重力坝基深层抗滑稳定分析

莫若嘎哈堪达水电站碾压混凝土重力坝坝基地质条件复杂,为更好掌握坝基面和深层抗滑稳定情况,本文选取4号溢流坝段为典型坝段,通过建立有限元模型,假设4号坝段存在两种滑动的模式,采用有限元法计算坝基深层抗滑稳定情况并进行分析,结果表明:在正常运行工况,4号坝段在两种滑动模式下的强度储备安全系数均为2.20～2.30,均大于混凝土重力坝设计规范值,因此4号坝段坝基满足抗滑稳定性要求,可为工程设计提供技术支持。     

由温度场研究坝基渗流初探

通过建坝前后地温场的变化了解坝基渗流状态是渗流监测中的新手段，１９９２－１９９５年对丹江口大坝坝基温度和库水温度进行了监测，同时对１９－３１号坝段坝基渗流进行了三维有限元模拟计算。     

云峰大坝缓倾角断层坝段抗滑稳定分析

云峰大坝50号-53号坝段基础存在缓倾角断层,对抗滑稳定不利。各种方法计算结果表明,不考虑侧向岩石抗剪,51号、52号坝段抗滑稳定安全系数不满足规范要求;考虑侧向岩石抗剪等有利因素,可满足要求。多年观测表明,变形在正常范围内,坝基扬压力较小,漏水量也不突出,大坝工作正常。侧向岩石抗剪等对51号、52号坝段抗滑稳定有一定作用,但不确定性较大,加上下游冲刷坑已接近坝趾,无尾岩支撑,应采取必要的加固处理措施。     

乌江沙沱水电站10号坝段涌水封堵施工

乌江沙沱水电站坝基岩溶发育,一期基坑10号、11号、12号坝段揭示多务岩1岩溶管道与河水相通,并在开挖面和见基面形戍多处流量很大的涌水点。为避免10号～12号坝段渗漏对工程质量及进度造成严重影响,确保大坝安全度汛和二期截流目标的实现．需及时对10号～12号坝段坝基涌水进行有效封堵,并对10号坝段已浇筑混凝土部位基岩进行充填和固结灌浆,以提高坝基的整体性。施工中主要采用模袋灌浆及灌注混凝土砂浆方法,最终将漏水堵住．确保基坑开挖和混凝土浇筑顺利进行,为今后类似工程的处理提供了一种有效的方法。     

百色水利枢纽重力坝6号坝段基础渗流场分析

百色水利枢纽重力坝基础岩体渗流特性复杂，6号坝段坝基有贯穿于坝基上下游的强透水层，岩体的成层性又呈现出渗透各向异性的特点，坝基渗流控制方案的设计是一个较复杂的问题。采用三维有限单元法及排水子结构技术，对6号坝段基础渗流场的特性和优选渗控设计方案进行了分析研究，对坝基坊渗帷幕和排水幕的工作机理和互存互辅的内在渗控关系作了明确的说明，为大坝的设计者提供有力的科学依据。     

某水电站厂坝复杂基础处理设计

某水电站河床分布的F1、F107、f100等组成一个较宽的断层破碎带,其位于10～13号坝段,并穿过3～5号机组段。为此,设计人员进行了大量的分析研究工作,参考国内外经验,在对坝基采用混凝土塞、深孔固结灌浆、防渗墙、加强帷幕等手段处理的同时,对断层破碎带部位的上部结构也采取厂坝连接、坝段并缝等工程措施,以提高大坝整体性和抗滑稳定性。     

某水电站坝基扬压力异常原因分析

坝基扬压力监控在重力坝安全监控中占有十分重要的地位,通过对某水电站坝基扬压力监测资料的定性分析发现,5号坝段坝基扬压力测值偏高,并有逐渐增加的趋势。进而通过扬压力折减系数、简单相关系数法、统计模型法、综合成因分析法等方法对该坝段进行定量分析,发现该坝段测孔扬压力折减系数偏大,测孔水位与上游水位相关性较大,进一步证明5号坝段下游侧可能存在潜在渗流通道,应加强监测,并在必要时采取工程措施。     

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。