三峡工程泄洪深孔工作弧门安装工艺

为满足大坝在不同蓄水高程的泄洪要求，在坝体的泄洪坝段设置了大量的泄洪建筑物，主要包括底孔、深孔和表孔三层泄洪孔洞，各层泄洪孔洞分别布置有多道工作弧门及埋件，其金属结构部分与土建部分结构复杂，施工技术难度大，工序错缩复杂，且施工手段极为有限，特别是深孔工作弧门的安装直接牵涉到坝体土建上升的工期及后期工作弧门安装工序的难度及强度问题，如何在不影响坝体土建施工，又能快速优质地在预期的工期目标内完成大量的工作弧门的安装，其安装工艺将取到决定性的作用，是在坝体施工的各种制约条件下，针对深孔工作弧门的施工特点，制定和优化了满足不同施工条件的施工工艺。     

三峡深孔弧门全部安装完毕

2001年12月18日上午,由葛洲坝机电建设公司承担施工的泄洪坝段20号深孔工作弧门完成门体与支臂的联接.至此,泄洪大坝深孔工作弧门全部安装完毕,为2002年8月大坝深孔一线具备挡水条件奠定了良好基础. 泄洪坝段共安装23扇深孔工作弧门,每扇工作弧门总重为245 t,葛洲坝机电建设公司负责深孔工作弧门的全部安装任务.2000年8月,第1扇深孔工作弧门开始安装. 为确保施工进度,葛洲坝机电建设公司提前准备了9套施工方案,在施工过程中根据不同的施工条件选取最佳施工方案,并不断优化改进.为加快施工进度,该公司在13个深孔中采用了敞孔吊装方案.以往采用闭孔吊装方案安装1扇深孔工作弧门需用15 d,而改用敞孔吊装方案后仅用7 d就可完成1扇深孔工作弧门的安装.该公司设计制作了3套施工装备,在无法采用敞孔吊装的部位,他们同时打开3个施工面平行作业.为减少对施工现场的干扰,该公司在进行支臂、门叶的吊装前,在加工厂内提前完成部件的预拼装.此外,该公司还打破传统的安装方式,采用倒装法进行闸门安装.当二期门槽混凝土还未完成浇筑时,他们就先装闸门,后装门槽,为确保工期赢得了宝贵时间. (长江)     

重庆江口水电站中孔弧门安装施工技术

由于受坝体结构的影响,重庆江口水电站中孔弧门在安装过程中遇到了很多吊装上的难题.由于在中孔弧门安装时,坝体混凝土正在上升,大型的吊车不能进入施工现场进行吊装作业,现场的吊装设备只有20 t辐射式缆机,满足不了大件安装的要求.中孔弧门按工期要求必须在讯前安装完毕,具备防洪挡水功能.所以,只能采用其它灵活可靠的施工方法.简要介绍了中孔弧门安装技术.     

瑞丽江一级电站大坝表孔弧门及液压启闭机安装

简述大坝溢流表孔弧门及液压启闭机主要技术特性、设备现场吊装方案、安装施工工艺、安装质量控制、液压启闭机调试及液压试验、油泵试验、弧门无水启闭试运行、弧门在设计水头下动水启闭试运行等情况，确认弧门及液压启闭机安装施工质量符合设计标准、厂家技术要求及规范中明确的优良标准，完全满足首部工程防洪度汛、水库下闸蓄水及汛期水库水位的调节需要。     

光照水电站预应力锚索吊装定位与控制

光照水电站大坝工程底孔及表孔闸墩预应力锚索数量多,且施工工期紧、技术要求高。本文对比介绍了大坝底孔和表孔闸墩预应力锚索吊装定位施工工艺,其中表孔闸墩预应力锚索吊装定位施工的技术改进确保了锚索吊装定位满足质量要求和闸墩混凝土浇筑的进度要求。     

三峡工程泄洪深孔弧形闸门安装工艺研究与应用

针对三峡第二阶段工程泄洪坝段深孔工作弧门的布置结构特点，结合现场布置的各种施工手段和土建施工条件，提出了适合各种限期条件下的多种施工方案，并在工程实践中推广应用，解决了施工中吊装手段不足、各种工序相互影响等技术难题。     

小湾双曲拱坝孔口坝段闸墩倒悬体及支承大梁设计与施工

小湾电站左岸大坝共布置有2号导流底孔、2号放空底孔、5、6号泄洪中孔及4、5号泄洪表孔,所有孔口坝段均设计有上下游闸墩倒悬体结构,闸墩倒悬体结构在下游孔口部位还设计有启闭工作弧门的支承大梁,倒悬体及支承大梁作为小湾大坝孔口坝段泄水的重要土建结构,该结构体形复杂,施工难度大,质量要求高,本文通过对孔口坝段倒悬体及支承大梁的设计和施工进行介绍,为后续类似工程积累施工经验。     

大藤峡超大型三支臂潜孔弧门制造技术

在水利水电施工建设中,弧形工作闸门是水电工程正常运行、水位调节和泄洪安全控制的重要永久性金属结构设备。安装在大坝底孔,承担泄洪、冲砂、发电等功能,其使用特性要求在门叶顶部、底端、两侧面均需保持有效密封,能够在任意开启位置停留,对设备承载、密封、转动性能有很高的质量精度要求。潜孔弧门的制造要求高,特别是超大型三支臂、纵向分节、弧面加工的潜孔弧门制造难度更大,本文就工厂制造的工艺技术分享与交流。     

浅谈万家寨大坝标的调差补偿

中国水利水电第四工程局投标承建的万家寨水利枢纽第1标——大坝工程,从1994年10月开始施工,经过建设者们近四年的努力,截止1998年7月底,5条排沙钢管、6条引水钢管已全部贯通;大坝已有7个坝段达到设计高程982米;电站进水口快速门、大坝泄洪底孔弧门、排沙孔进口门已全部安装就位;主体工程155万立方米混凝土已浇筑140万立方米。年底首台机组发电的目标有望实现。随着机组安装工作的陆续投产,大坝工程的后期调差及补偿问题也摆在了施工承包商与建设管理单位面前。     

小湾水电站2号放空底孔事故检修闸门整体门槽安装技术

小湾水电站大坝放空底孔事故检修门门槽工作段采用整体门槽形式,因闸门工作水头高达160m,整体门槽的安装精度要求很高。由于设备到货严重滞后,施工环境及条件发生较大变化,因此需根据实际情况重新制定整体门槽的安装施工技术措施。本文详细介绍云南省澜沧江小湾水电站2号放空底孔事故检修闸门整体门槽的安装过程,包括设备的吊装、安装调整、测量控制及验收检验等方面的内容。     

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。     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.     

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。