三峡三期工程背管混凝土施工

三峡三期工程IA标段布置有6条引水压力管道，结构复杂、施工空闯相对狭小、钢筋量大。针对背管的特点，采取配置异型钢模板、钢筋安装优化、应用高流态混凝土、钢管底部布设回填灌区等措施，保证了背管混凝土的施工质量，提高了施工效率。     

龙滩水电站进水口金属结构安装质量监理

龙滩水电站进水口金属结构主要安装项目为引水压力钢管、闸门槽埋件、拦污栅槽埋件、清污导槽埋件、平面滑动钢闸门、拦污栅体、坝顶门机、清污门机、液压启闭机。因厂房蜗壳前段引水压力钢管在蓄水后还不能进行安装，闸门挡水要求保证滴水不漏，安装工作任务重、工期紧、难度大、质量要求高。通过实施金属结构安装质量监理控制等措施，确保了金结安装工程的质量，完成了2006年9月底提前下闸蓄水的预定目标。     

三峡三期大坝压力钢管外包混凝土施工技术

三峡三期工程要全面实现快速一流，其施工方案研究与实施贯穿于施工与管理的全过程。在三峡三期大坝压力钢管外包混凝土施工中，通过优化施工方案，研究施工技术、实施精细化管理，确保了三期大坝压力钢管外包混凝土施工如期完成且工程质量达到一流。     

溪洛渡水电站右岸引水压力钢管安装

溪洛渡右岸地下电站10号～18号共装机9台，每台机组都拥有独立的引水压力管道，其中压力钢管设置在引水下平洞，其上游与引水竖井的下弯段相接，下游与蜗壳相接。从压力钢管安装为出发点，分析压力钢管的安装难点，总结经验，不断完善压力钢管的安装工艺为目的，简述压力钢管安装方法和质量控制过程。     

空间转弯段压力钢管的安装

本文对丰满电站三期工程的压力钢管空间转弯段的安装作了详细的介绍，重点阐述了钢管的洞内运输方法和空间转变安装控制尺寸的计算，通过安装实践检验了运输方法是可行的稳妥的，并利用计算的结果在安装中的实施，保证了钢管安装的设计精度尺寸，同时由于采取了合理的施工方法和安全措施，保证了施工进度，收到令人满意的效果。     

三峡工程压力钢管凑合节安装技术

三峡工程压力钢管直径为12．4m，钢管分阶段安装，最后利用凑合节实现整条钢管的合拢，在传统的施工中，凑合节采用瓦片的形式进行安装，并根据现场实际情况确定瓦片的块数。一般情况瓦片的数量不少于3块。为进一步提高压力钢管的安装质量，通过试验论证和施工技术准备，拟定三峡三期压力钢管凑合节采用整体形式安装，由于管径大，施工难度大，该技术代表目前国内压力钢管安装的先进水平。     

阿海水电站引水压力钢管凑合节安装工艺

阿海水电站引水压力钢管安装工期较紧,采取一般的凑合节安装方法,占用工期较长且工作量大。本文主要讲述引水压力钢管凑合节的安装、配割方法,通过阿海水电站引水压力钢管安装的实践,总结了阿海水电站引水压力钢管凑合节的安装经验。     

白石水库压力钢管设计与施工的监理质量控制

白石水库工程设取水压力钢管1条，电站引水压力钢管3条．在压力钢管施工图审批中，对灌浆孔布置、取水钢管进口方变圆渐变段等做了设计修改；制造与安装过程中重点控制了钢管圆度、焊接、弯管组装、始装节和波纹管膨胀节安装等工艺．实践证明，监理质量控制切合实际、重点突出、措施周到、成效显著．     

乌东德水电站左岸引水隧洞首节压力钢管成功吊装就位

正9月20日,由葛洲坝三峡建设公司乌东德施工局承建的乌东德水电站左岸引水发电系统6号引水隧洞下平段首节压力钢管成功吊装就位,此举标志着乌东德水电站左岸地下电站水轮发电机组部分安装工作正式启动,为后续左岸地下电站首台(6号)机组发电奠定了良好基础。乌东德水电站左岸地下厂房共安装6台单机容量85万千瓦的水轮机组,其引水隧洞采用一洞一机平行布置型式。压力钢管布置在引水下平段,顺水流经下平段、锥管段、连接段至水轮机蜗壳进口。左岸6台机的6条压力钢管长度均为55.2米,总长约331.2米,内径13.5至11.5米不等,压力钢管管壁全部采用     

论玻璃钢管道安装的质量控制

本文以石门引水工程玻璃钢管安装为例,论述了管槽开挖、管道安装前期准备、管道现场制作、玻璃钢管安装、压力试验、压水试验等质量控制要点,旨在为玻璃钢管施工提供经验与供供鉴。     

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。     

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.     

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.