南水北调中线工程金属结构及机电项目管理探讨

结合南水北调中线京石段应急供水工程(委托河北建设管理项目)金属结构、机电项目管理特点,重点介绍了金属结构及机电设备制造安装管理体系和设备制造、安装全过程质量监控措施,对特大型水利工程的金属结构、机电项目管理经验进行了探索和总结,对类似工程的管理起到参考和借鉴作用.     

机电安装电气设备预埋存在的常见问题及对策

正目前,伴随着各种技术的日新月异的发展,各行业中的机电设备及其用电量在也在不断的增加,机电安装相关工程作为整个机电行业工程项目中非常重要的一个环节,它包括了工业、公用、民用等工程中的各类相关设备,通信及自动化控制系统的安装等,因而对于加强各种工程设备安装的过程管理,确保安装质量,早已成为建筑施工企业管理工作中的重中之重。就目前来说,我国的机电电气     

抽水蓄能电站机电设备安装技术管理

抽水蓄能电站机电安装工程是一个多目标的复杂的系统工程,设备在安装过程中由于安装环节相对较多,并且经常会出现交叉作业的现象,在不同的安装阶段需要运用不同的安装技术,为更好保证机电安装工程安全、质量、进度目标的实现,需结合抽水蓄能电站工程实际特点机现场需求,制定符合本电站机电安装工程工期优化的方向和目标。对抽水蓄能电站机电设备安装技术管理进行探讨,在分析其安装要点和安装难点的基础上,具体论述抽水蓄能电站机电安装工程水轮机、发电机等环节的安装过程中的技术管理措施方法,希望能够为同业人员提供一定的借鉴参考。     

湖北堵河小漩水电站机电安装工程施工质量控制

为更加科学有效地控制水电站机电安装质量,分析和汇总了湖北堵河小漩水电站机电安装工程中主要设备的施工质量控制经验,阐述机电安装施工的控制策略和方法。     

安装工程的施工管理

随着我国的经济水平发展速度的不断提高,机电安装的技术也越来越高超,因此,建筑事业的发展空间也变得更大更广阔了。在工程施工的时候,机电设备的安装是施工质量是否达标的基础,因此,机电设备的安装管理必须得到加强,从而保证施工的质量。1.机电设备安装1.1机电安装特点随着经济水平的发展,我国的工业规模越来越大,机电安装也成了越来越大的工程,而建筑企业的机电安装工程尤为复杂,这类工程要求相关工作人员拥有较广的知识面,而安装者又必需要懂得新的技术,新的工艺以及新的设备的各种知识,总的来说,机电安装工程的技术含量相对较高,相关工作者应在施工的过程中不断学习,以提高自己的能力。     

泸定水电站机电设备安装创优质量管理概述

泸定水电站机电及金结设备安装工程的质量管理分为创优策划编制、质量保证和质量控制3个层次.机电安装的各级管理人员,包括监理工程师需在工程项目的实施过程中严格按照上述3个阶段进行,才能保证工程质量控制顺利有效的落到实处.并以电缆二次接线施工创优策划为实例加以说明.     

贵州都柳江从江航电枢纽工程机电安装工程管理研究

本文通过介绍贵州都柳江从江航电枢纽工程的工程概况,分析了航电枢纽工程机电安装工程管理中存在的难点和问题,即进度问题、质量问题和安全问题。同时针对这些问题提出了应对措施和建议,以期使相关技术人员对航电枢纽工程机电安装工程管理在原有的基础上有更系统、全面、深入的认识和了解,有助于航电枢纽工程机电安装工程管理的优化。     

业主主导作用在大朝山工程机电项目管理中的体现

介绍了为业主主导作用在大朝山工程机电项目管理中的体现，即从机电技术管理开始，到设备选厂、驻厂监造、进度计划管理、安装技术准备、监理单位的组建成套设备管理全过程中的体现，以及在进度控制，质量控制，费用控制等方面所取得的成效。     

三峡工程Ⅰ&ⅡB标机电埋件和设备安装监理

机电监理工作具有工程项目多、分布坝段广、专业覆盖面宽、进度受控于土建及设备供货等特点.结合三峡工程Ⅰ&ⅡB标机电一期埋件和设备安装工程的监理实践,对机电工程质量监理特性进行了分析总结.对设备开箱、材质检查、现场验收、安装调试等关键工序的监理工作或重点部位,提出了有效的控制程序.经监理严把质量关,严格执行验收和各项质量管理制度,确保了机电埋件和设备安装满足合同文件、设计图纸及规程规范要求,机电埋件安装合格率达到100%.泄洪坝段底孔弧门启闭机于2001年12月26日完成全部电气项目调试,单元工程评定为优良,2002年5月30日已正式移交给三峡电站筹备处.     

水电站机电安装项目管理要点分析

机电安装项目管理是水电站建设工程的主要构成部分,其安装质量严重影响着工程总体质量,尽管我国已出台诸多相关政策与措施,但机电安装工程项目的质量问题依然偶有发生,直接影响着水电站的安全。对此,要从施工设计和组织协调等诸多方面提升管理水平,保证水电站的机电安装工程项目的总体建设质量,另外还应该积极应用先进信息化管理技术,创建水电站安装工程的管理信息化平台,提高建设效率,确保水电站工程项目的整体建设质量。     

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.     

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.     

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。     

Desiccation and recolonization of phytobenthos in a regulated desert river: Colorado River at Lees Ferry,Arizona, USA

We tested the recolonization of the phytobenthic community in the tailwaters of Glen Canyon Dam following long- and short-term experimentally induced desiccation. The response of Cladophora glomerata, Oscillatoria spp., miscellaneous phytobenthos species and periphyton was studied over 18 weeks using three treatments: (1) undisturbed control cobbles from the submerged zone; (2) cobbles desiccated and replaced into the submerged zone; and (3) cobbles desiccated and replaced into the varial zone. Periphyton density and compositional response resulting from these treatments were also examined. Desiccation treatments were significantly different in biomass from controls throughout the study. The biomass of desiccated and replaced river cobbles averaged <30% of the controls for C. glomerata and periphyton during the 18-week recolonization period. In contrast, the biomass of the control Oscillatoria and miscellaneous phytobenthos species averaged only 3 and 50% of that in the desiccation treatments, respectively. Cladophora, the dominant alga, comprised 77% of the phytobenthic biomass. A significant positive relationship between discharge, Cladophora and periphyton biomass was present in all treatments, while there was a negative relationship with discharge for Oscillatoria and miscellaneous phytobenthos species. There was a significant inverse correlation, as well as a pattern of separate biomass dominance, between C. glomerata and Oscillatoria. Cladophora was the dominant phytobenthos species on cobbles below the baseflow and Oscillatoria was dominant on cobbles in the varial zone. In general, the Cladophora biomass decreased under intermittent drying conditions, while Oscillatoria declined under permanently wet conditions. Diatom composition was not significantly different between treatments; however, their density was lower on desiccated cobbles. Diatom density on desiccated cobbles in the submerged and varial zones averaged 69 and 42% of that of the controls, respectively. Recovery and maintenance of benthic resources are hindered by fluctuating flow regimes driven by electricity and irrigation requirements. Repeated desiccation of the phytobenthos has major effects on the bottom-up interactions in the Colorado River ecosystem. © 1998 John Wiley & Sons, Ltd.