杨家杖子供水工程中途加压泵站水泵选型设计

水泵选型对于山区城市供水工程具有重要的意义。本文以辽宁省葫芦岛市杨家杖子供水工程为实例,基于中途加压泵站水泵运行工况,分析确定了该供水工程中途加压泵站水泵运行台数,并就水泵选型设计比选中的调速方式进行了探讨,进一步验证了三用一备全调速泵方案的合理性,以期对类似工程水泵选型有所借鉴。     

泵站工程水泵机组选型及水锤防护探讨

水泵是泵站提水加压的主要设备，水泵机组及配套附属设备的选型是整个泵站设计质量控制的核心。结合流量、扬程、输水介质及安装环境等影响因素，从水泵型式比选、运转工作点判定、机组台数组合和水锤防护等方面，对机组型式及参数选择的技术关键进行了详细论证分析，给出较优的组合方案以确保泵站工程具备较好的运行安全性和节能经济性。     

观景口泵站水泵选型设计分析

观景口水利枢纽工程是重庆市重点水源工程之一,工程任务以城市供水为主,同时兼顾小城镇及农村人畜饮水、农业灌溉。泵站从水库通过压力输水隧洞总管引水,在泵站前叉成支管进入泵组,经水泵加压后,汇成一根出水总管至出水池。水泵扬程范围为18.83 m～48.46 m,运行初期设计流量为0.5 m~3/s,设计水平年设计流量为4.76m~3/s,比较选定4台套大泵、2台套小泵匹配变频运行。     

乐甲泵站水泵选型方案比选

大伙房水库输水应急入连工程是向大连市供水的长距离供水工程,其中泵站水泵选型方案的合理设计对节省工程的一次性投资、运行费用及方便工程运行管理等具有十分重要的意义。本文从技术和经济两方面对乐甲泵站水泵选型进行比较,最终选择较优的方案,为大连应急供水工程设计提供参考。     

惠南庄泵站一大型高扬程水泵机组选型设计与运行方案研究

惠南庄泵站是南水北调中线工程总干渠唯一的一座大型加压泵站，是北京段实现管涵加压输水的关键控制性工程，也是中线工程的标志性建筑。泵站为大（Ⅰ）型Ⅰ等工程，单机容量大，特征参数变幅大，机组采用变频调速运行，调速范围大，运行工况复杂，技术难度高，国内外没有可参照的工程实例。现结合工程特点着重对大型、高扬程水泵机组的选型及运行匹配等主要技术问题进行分析研究。     

供水工程加压方案的选择分析

合理选择输水工程的加压泵站方式,对工程投资和将来的运行管理有较大的影响。结合平潭综合实验区近期调水工程中加压泵站的选择,分析一级加压及二级加压的优缺点;结果表明采用分级加压对于部分引水工程中,在工程线路布置、运行管理等方面均有一定的优势,可供类似工程借鉴。     

高效节水灌溉工程水泵机组选型及配套问题的探讨

高效节水灌溉设计包括水源工程、系统选型、首部枢纽和管网设计。其中,水泵是必不可少的加压设备,主水泵与配套的动力机械等装置,是整个泵站的核心。水泵选型配套是否合理,不但直接影响泵站功能的实现和一次性工程投资,同时也影响到工程运行的费用和便利性以及整个工程运行安全性等问题。针对高效节水灌溉工程设计中水泵机组选型和配套容易出现的一些问题进行了探讨。     

南水北调东线工程泵站电机过载问题研究

分析南水北调东线工程梯级泵站水位组合、扬程情况及所选用水泵的轴功率特征，从设计制造、施工安装和运行条件等方面研究影响水泵运行轴功率并可能造成配套电机过载的主要因素及其概率特征。提出基于可靠度的水泵配套电机功率备用系数的计算方法，计算本工程三种水泵扬程和两种清污条件的源头泵站和非源头泵站电机功率备用系数。成果对大型泵站电机的合理选用，提高机组运行可靠性和效率，节省设备投资有重要意义。     

惠南庄泵站大型高扬程水泵机组选型设计与运行方案探讨

惠南庄泵站是南水北调中线工程总干渠唯一的一座大型加压泵站,是北京段实现管涵加压输水的关键控制性工程,也是中线工程的标志性建筑.泵站为大(Ⅰ)型一等工程,单机容量大,特征参数变幅大,机组采用变频调速运行,调速范围大,运行工况复杂,技术难度高.结合工程特点着重对大型、高扬程水泵机组的选型及运行匹配等主要技术问题进行分析研究.     

大中型长距离梯级有压管道供水泵站水泵系统设计关键问题总结探讨

大中型、长距离梯级有压管道供水泵站的水泵系统设计不仅需综合考虑泵站梯级设置、泵站水锤防护、梯级泵站流量平衡等系统设计的关键问题,还需解决泵站的变工况计算、水泵调节工况计算、节能运行方式等问题。就东莞市东江与水库联网工程中的主体工程-供水水源工程探讨长距离梯级有压管道供水泵站的水泵系统设计应注意的关键性技术问题。     

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…