枕头坝一级水电站正常蓄水位比选分析

正常蓄水位是确定水电站规模和水库淹没影响范围的重要参数。针对枕头坝一级水电站的开发任务和工程特点,综合考虑水库淹没、环境影响、工程建设条件与枢纽布置及经济指标等多方面影响因素后,从拟定的4个正常蓄水位比选方案中,选定枕头坝一级水电站正常蓄水位为624 m,侧重考虑了水库淹没与库区经济、社会的协调发展,体现了大渡河水电开发具有合理开发利用水能资源、开发与保护并重、努力实现多方和谐共赢的水电开发新特点。     

关坝水库蓄水位选择分析

决定水库蓄水位高低的因素主要有工程环境、水库最高蓄水位、最低蓄水位、水库下游蓄水量及工程投资和淹没损失等,文章通过对关坝水库水位选择进行探讨,从充分利用水资源方面考虑,随着水库正常蓄水位的增加,水位为817-829m时水库供水量的增加与水位关系基本为线性增加关系,正常蓄水位越高供水量越大。从淹没损失方面考虑,由于825m高程以上分布有村寨,水位抬高后将导致淹没投资大幅增加,最终选择关坝正常蓄水位为823m。     

花甲水库正常蓄水位选择

正常蓄水位是水库和水电站最重要的设计参数之一,是确定拦河坝高度、水库容积、利用水头和发电能力的基本依据;对水工建筑物的工程量、水库调节性能和水头的利用关系极大,对水库和水电站的建设工期、投资、动能经济效益以及水库淹没损失等均有重要影响。文章以花甲水库工程挡水坝的正常蓄水位选择为例,从水库供水量、水库淹没、工程投资对水库正常蓄水位的影响等方面做简要分析论证。     

水库淹没调查在水利水电工程建设中的重要性

1水库淹没实物指标调查的意义工程建设规模的确定,是以经济、社会、环境效益为最大,而淹没损失相对较小为条件。一般在水库工程建设的前期阶段,都要对不同设计蓄水位做方案比较。调查不同正常蓄水位的淹没实物指标,把水库淹没、移民安置与当地社会经济、财力、生态环境等诸多因     

西藏金河流域瓦托水电站正常蓄水位选择

水电站正常蓄水位的选择,不仅需要考虑工程建设条件、生态环境、水库淹没影响、投资及动能经济等因素,还应考虑与上下游水电站的衔接以及联合调度产生的综合效益。以西藏金河流域瓦托水电站为例,重点介绍与上游勒珠水电站衔接时,以其动能、经济指标和在电网发挥作用的综合效益,来选定正常蓄水位。由于瓦托水电站库区淹没影响小,无国家珍稀动植物分布,无通航要求,电站正常蓄水位的确定主要考虑梯级水库水位銜接、经济效益、电网调峰等因素。经综合比较,最终确定瓦托水电站最优正常蓄水位为3 315 m。     

珊溪水库工程正常蓄水位选择

通过对两个正常蓄水位方案发电量、投资、水库淹没指标等的分析，并对方案进行经济比较，综合分析确定珊溪水库正常蓄水位。     

已建坝正常蓄水位调整论证方法研究

已建坝正常蓄水位调整是挖掘水库兴利能力的有效途径，但目前缺乏明确可靠的论证方法。采用水文学、大坝安全、大坝风险及生态环境理论，研究已建坝正常蓄水位调整必要性的影响因素及特征，分析调整后水库防洪安全、工程安全、库区淹没、库岸结构、库区水环境所受影响特征，提出了正常蓄水位调整必要性论证的6个一级、14个二级指标体系，以及调整后影响论证的7个一级、23个二级指标体系及其分析方法，构建调整方案风险效益分析方法，并应用于杭州青山水库正常蓄水位调整论证。结果表明：针对青山水库将正常蓄水位提高2.0 m的推荐方案，提出的论证指标体系和论证方法合理有效。     

胜利水电站正常蓄水位方案选择

<正>常蓄水位选择是水电站设计工作的一项重要任务。本文以胜利水电站为例,分别从梯级电站水位衔接、水能资源利用、水库淹没和工程经济评价四个方面出发,阐述了水电站拦河坝正常蓄水位的选择过程,分析了影响正常蓄水位的制约因素,并通过合理比选,最终确定了胜利水电站的正常蓄水位方案。     

乌东德水电站正常蓄水位抬高初步研究

成昆铁路的提速改造为修改乌东德水电站原订的950 m正常蓄水方案提供了有利契机,可使乌东德水库正常蓄水位抬高几十米。从水库正常蓄水位抬高对成昆铁路、及攀枝花市防洪及水环境、雅砻江口生态环境的影响以及水库淹没指标、工程经济效益等方面进行了综合分析。分析结果表明,乌东德水电站正常蓄水位提高至975 m,可获得较好的经济效益,且对环境、防洪、移民的负面影响不大。     

花园水库淹没影响范围确定方法探析

水库淹没影响范围包括水库淹没区和因水库蓄水而引起的影响区。水库淹没区包括正常蓄水位以下的经常淹没区和水库正常蓄水位以上因水库洪水回水、风浪、船行波、冰塞壅水等产生的临时淹没区。水库蓄水引起的影响区包括浸没、坍岸、滑坡、内涝、水库渗漏等地质灾害区,以及其他受水库蓄水影响的区域。     

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。     

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.     

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。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。     

Fish assemblage response to recent mitigation of a channelized warmwater stream

Various designs of low‐head dams are used to rehabilitate streams or forestall upstream channel incision after channelization. We report on the efficacy of using notched sills and grade control structures (GCS) to restore the fish assemblage in Luxapallila Creek, Mississippi. We tested the null hypotheses that habitat variables and species richness, evenness, and assemblage structure would not differ among: (1) a channelized segment with no modifications; (2) a channelized segment mitigated by the installation of sills and GCS; (3) a segment upstream of the installations and undergoing channel incision; and (4) an unaltered segment. Although habitat variables changed, neither species richness, evenness, nor fish assemblage structure differed between mitigated and channelized segments with both exhibiting less richness and different assemblage structures than the unaltered segment. Lack of differences in species richness between the incised and unaltered segments suggest that the GCS may have halted the negative effects of upstream channel incision before species were extirpated. Conspicuous habitat differences between the altered (channelized and mitigated) and unaltered segments were lack of backwaters and canopy coverage and finer substrates in the altered segments. Our results suggest a more comprehensive rehabilitation strategy is required in Luxapallila Creek. Published in 2003 by John Wiley & Sons, Ltd.     

NUMERICAL STUDY OF WAVE EFFECTS ON SURFACE WIND STRESS AND SURFACE MIXING LENGTH BY THREE-DIMENSIONAL CIRCULATION MODELING

1. INTRODUCTION Coastal and continental shelf regions are characterized by intensive interaction between wave and current. These regions are of great economic significance to mankind. Therefore, the modeling of wave and current as well as their mutual int…