瀑布沟水电站机组轴线的调整

以瀑布沟水电站4号机机组轴线调整为例，介绍在弹性状态下盘车轴线处理的方法，对连续盘车3圈后定点停读的盘车摆度数据、从6号盘车点位向2号盘车点位推020?ｍｍ后的盘车摆度数据、推力头旋转180°把紧联接螺栓后的盘车摆度数据、加垫且推力头把合螺栓对称均匀把紧后的盘车摆度数据进行比较，以期为类似机组轴线调整提供经验。     

格里桥水电站1号机盘车及轴线处理

为减少机组运行振摆,减轻转动部件不平衡力,通过盘车分析调整机组轴线在合格范围内,是机组安装、检修中的一项重要工作,盘车目的是检查机组轴线的倾斜和曲折状况,根据测量所得的数据,对影响轴线的关键部位进行加垫或刮削处理,使轴线满足规范要求。笔者以格里桥水电站1号机为例,介绍盘车及轴线处理。     

挂线法在官地水电站水轮发电机轴线检查中的应用

为减少官地水电站水轮发电机组后期轴线的处理难度,以及加快施工进度,采用挂线法对官地水电站2号机组水轮机大轴、发电机大轴连轴后的轴线进行挂线测量检查,由挂线测量数据分析轴线是否超标,为轴线的提前处理提供理论依据。结果表明挂线法具有操作简单、分析准确的特点,通过前期的静态挂线测量,可为机组整体轴线的调整提供依据,可以减小后期轴线的处理压力。     

小山水电站1号机组振动摆度综合治理

针对松江河发电厂小山水电站1号机组摆度过大问题，在1号机组首次扩修过程中，对机组轴线进行了全面调整，同时对转子重新进行动平衡处理。通过多次摸索，开创性地用强迫垂直的方法对弹性油箱式推力轴承机组进行轴线调整，并采用动平衡的方法对磁不平衡进行补偿，解决了机组运行时的摆度超标问题，保证了机组的安全稳定运行。     

浅谈减小机组振动摆度的方法

通过对赤道几内亚吉布洛水电站1号机组转动部分振动摆度超标消缺处理的介绍,总结了小型机组轴线调整和轴瓦调整的方法,以及造成机组运行过程中振动摆度超标的原因。     

二滩水电站机组水导、下导甩油处理方法

主要介绍了二滩水电站第一台机组（6号机）在72h试运行时，发现水导、下导甩油后，按甩油的具体情况，由业主、工程师、加拿大GE公司及承包商共同研究后，对6号机及其它机组做了相应的结构改进，并在其余机组上成功实施了改进方法，可为其它水电站解决类似问题提供一些有益的经验。     

青居水电站2号机组水导轴承烧瓦处理

介绍青居水电站2号机组水导轴承烧瓦后的处理过程:进行机组拆机检查;对烧损的水导轴瓦采用非常规的修复方式;通过对水导轴瓦修复后的数据分析,确定加工水导轴承法兰面,使大轴与水导轴瓦间隙符合设计要求;调整扇形板的高度,使机组轴线符合设计要求;检查机组间隙合格后,恢复青居水电站2号机组发电。     

思林水电站4号水轮发电机组盘车轴线检查分析及轴瓦间隙调整

思林水电站4号水轮发电机组大修中,通过盘车试验检查机组轴线,根据盘车数据调整各轴承瓦的间隙,确保了4号机组大修后的安全稳定运行.     

锦屏二级水电站水发联轴镗孔工艺应用

在水电站机电安装过程中,机组轴线状态的检查与调整是非常重要的工序,其质量好坏是机组长期安全稳定运行的关键因素。在工地,检查机组轴线状态的主要手段是联轴盘车,计算出各导轴承的摆度,特别是水导摆度,由于现在大型水电站设备制造均趋于分工合作,单独的一个制造厂很难满足设备制造质量和进度要求,这就为机组轴线状态埋下了严重的不确定性,在锦屏二级已完成的七台机组轴线调整中,有五台进行了较大的工艺加工,取得了显著的效果,水导运行摆度均在0.10mm左右,其中4~6号机水导运行摆度约0.05mm,机组运行稳定、性能优良。     

黄金坪水电站左岸大厂房4#机组轴线调整

介绍了黄金坪水电站4#机组在安装过程中采用的轴线调整方法。通过对盘车数据进行计算和分析处理,解决了机组导轴承摆度过大的缺陷,最终完成了机组轴线调整,机组运行后摆度及振动达到规范要求。     

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。     

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.     

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.