表孔弧形闸门空载启闭异常振动原因试验研究

针对江山碗窑水库5#表孔弧形工作闸门空载启闭过程中存在异常振动问题,通过弧门支铰及埋件位置现状检测、不同开度下弧门位置检测、振动测试、工作应力测试、启闭力测试等原型试验以及弧门振动模态理论分析,对弧门异常振动的原因进行了深入的研究。研究结果表明：弧门上主梁左右2测点（原同一高程）的高程差随弧门开度的增加而增加,当弧门开启7.6 m时,高程差达88 mm,这和左侧支铰轴高层偏差均超标是引起弧门异常振动的2大因素;弧门异常振动主要发生在4.39 m开度内,为刚体模态中绕上轴线的旋转振动;该振动在左支臂上表现尤其显著。研究成果对表孔弧门异常振动运行的安全评估和故障处理具有重要参考价值。     

船闸闸门三支承铰连接螺栓断裂研究

针对船闸闸门三支承铰连接螺栓存在的断裂问题，结合对其进行的检测与研究，分析了支铰连接螺栓断裂的原因，指出支铰连接螺栓的断裂主要是由于三支铰轴不同心、支铰轴同心度存在较大偏差所造成的；同时，螺栓材质选用不当及螺栓松动亦加速了螺栓的断裂．此外，进一步分析研究了闸门在不同支承约束情况下构件应力的分配变化规律，提出了改进措施和建议，从而消除了螺栓断裂隐患，确保船闸的运行安全。     

新桥船闸闸门支铰连接螺栓断裂分析

针对新桥船闸闸门支铰连接螺栓存在的断裂问题,结合现场检测结果,分析了支铰连接螺栓断裂的原因,指出其断裂主要是闸门上、中、下支承铰轴不同心,支铰轴同心度存在较大偏差所造成的;同时,螺栓材质选用不当及螺栓松动亦加速了螺栓的断裂.进一步分析了闸门在不同支承约束情况下构件应力的分配变化规律,并提出了改进措施和建议.     

三河闸闸门支铰响声现象分析及处理

三河闸从1995年以来发现14孔闸门支铰有异常响声,造成闸门支铰异常响声的原因有：支铰轴尺寸偏小,轴套承受压力大；轴套承压区域润滑不良；轴与轴套的配合间隙小,磨合期短；闸门制作安装偏差影响支铰运行.经几年的摸索实践,采取以下做法消除了闸门支铰异常响声：适时足量加油润滑,改善支铰的运行工况；调整侧滚轮与止水座的间隙,改善闸门的运行工况；调整钢丝绳长度.     

考虑水封阻力影响时弧形闸门支铰反力的数解法

对求解弧形闸门支铰各反力大小及方向的现行规范和其他一些参考资料,都是采用图解法,而未将水封摩阻力考虑进去。水封摩阻力沿弧线分布,各点的方向和大小不同。根据实践经验证明,水封(参见图1)摩阻力,特别是侧水封摩阻力不可忽略,尤其在高压弧形闸门设计中,它是一个相当大的力,对启闭力的大小和支臂断面的设计都有很大的影响。为此,本文提出了考虑水封阻力影响计算弧形闸门支铰反力的数解法及侧水封摩阻力的计算方法。 (一) 平衡力系计算当弧形闸门开启时,作用在其上面的     

糯扎渡水电站泄洪洞弧形闸门安装质量控制

糯扎渡水电站泄洪洞工作弧门有动水启闭和局部开启运行要求,闸门设常规和冲压水封（全关工况冲压水封止水）。监理工程师对闸门安装前的准备工作进行了逐一检查,分析了影响闸门整体安装质量的关键工序,确定了支铰大梁和支铰安装是弧形闸门安装的质量关键点;左右固定支铰轴孔的同心度、钢梁的倾斜度、左右支铰到孔口中心线距离、支铰轴孔中心连线到底水中心线的距离、二期混凝土浇筑导致的变形是安装质量控制重点。闸门安装完成后,经过调试和试运行,安装质量达到了较高水平。对整个安装过程作了详细介绍,可为同类工程参考。     

小湾水电站底孔弧形闸门支铰应力分析

将闸门和支臂及支铰作为整体考虑，在铰轴与活动铰链和固定铰座连接处采用薄层接触单元模拟其间只传递法向压力的特性，分析了正常工作荷载作用下支铰各部件的应力分布。计算成果表明，正常工作荷载作用下，小湾水电站底孔弧形闸门支铰各部件的应力分布合理,满足强度要求。     

三峡水利枢纽导流底孔闸门泄流振动监测与分析

对三峡水利枢纽工程导流底孔闸门动力安全监测资料作了介绍与分析,其中包括闸门的动力特性和在设计水位条件下闸门在动水启闭过程中的振动加速度、振动位移、动静应力、脉动压力和启闭力的监测成果。监测成果表明闸门的自振频率监测成果与闸门水弹性模型试验成果很接近,振型相同;在动水开门和关门过程中,闸门在小开度时,下游面底缘的脉动压力较大;闸门门叶和支臂的振动小开度比大开度的大,未出现危害性振动,各测点的振动位移和振动应力都比较小,闸门振动是安全的。     

芦潮港水闸弧形钢闸门与启闭机质量检测及卡阻原因分析

<正>弧形钢闸门与液压启闭机广泛应用于我国水利工程建设中，浦东芦潮港节制闸弧形钢闸门及液压启闭机运行时，闸门卡阻并伴有异常声响，影响工程运行安全。本文通过“三检测，一排查”，对既有工程弧形闸门支臂铰轴同轴度检测方法进行创新，科学分析产生卡阻的原因，为加固处理提供依据，供类似闸门情况参考。     

弧形闸门安装中常见问题及处理措施

分析了弧形闸门安装中常遇到的支座基础螺栓位置与支座螺孔位置不吻合、安装时支臂与门体连接螺栓位置不吻合、支臂连接后支臂总长度不符合设计要求、侧水封压缩不均匀或门体偏向一侧、闸门顶水封被撕裂或漏水、铰轴安装不能到位等问题。通过对处理措施进行探讨，以减少以后工作中此类问题的发生。     

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.