水电站短斜井混凝土衬砌滑模设计与施工控制

本文结合白石水库电站尾水系统斜井混凝土衬砌施工,分析了短斜井滑模体组成及其主要部件设计方案,介绍了混凝土衬砌施工技术控制要点,并针对工程施工常见的滑模体偏移问题提出了几种有效的纠偏措施。工程实践表明:该斜井滑模施工工艺具有工效高、工期短、质量好、施工安全等优点,在保证混凝土衬砌施工质量的基础上大大缩短了施工周期,节省了施工成本。     

液压提升系统在斜井混凝土衬砌施工中的运用

鲁地拉水电站6条引水隧洞斜井混凝土衬砌采用液压提升斜井滑模系统进行混凝土浇筑施工。该文着重介绍该套液压提升斜井滑模系统结构的特点及施工工艺流程。     

LSD斜井滑模系统在桐柏抽水蓄能电站的应用

陡倾角大直径长斜井混凝土衬砌施工技术复杂，施工难度特别大。卷扬机、钢丝绳牵引模体不适用于长斜井滑模。CSM公司研制的滑模系统不能连续滑升。液压爬钳滑模系统模体受力偏心，易发生故障。LSD斜井滑模系统属国内外首创，为陡倾角大直径长斜井混凝土衬砌施工提供了一种可靠的施工机具。     

深圳抽水蓄能电站斜井轨道施工技术

介绍深圳抽水蓄能电站水道系统土建工程斜井滑模轨道施工技术要点和施工工艺。深圳抽水蓄能电站斜井施工中将开挖、混凝土施工轨道整合施工并浇筑在衬砌混凝土中,即开挖轨道、混凝土滑模轨道进行1次安装且不拆除的施工方法,缩短了施工工期,降低了斜井轨道安装、拆除过程中潜在的安全风险。     

斜井液压拉升自导向滑模(YLZ)混凝土衬砌技术

陡倾角、大直径斜井混凝土衬砌施工难度大、危险性高、人工立模衬砌周期长,在戈兰滩水电站直径为7.5 m的斜井混凝土施工中,成功设计、应用了液压拉升自导向滑模(YLZ)系统,取得了较好的效果和经济效益。介绍了该滑模系统的设计、制作安装与混凝土施工衬砌技术。     

黑麋峰抽水蓄能电站长斜井滑模施工技术

黑麋峰抽水蓄能电站引水斜井混凝土衬砌,采用LSD斜井滑模系统连续不间断滑模衬砌施工,取得了十分满意的效果。本文简要介绍了该工程滑模施工的工艺流程,并对滑模台车的改进、施工中遇到的问题及施工安全等进行了总结分析。     

特大型断面斜井滑模混凝土施工技术

特大断面斜井滑模是一项新型斜洞衬砌混凝土施工技术。文章主要介绍龙滩水电站地下厂房系统工程引水斜井滑模施工的技术和施工方法,包括滑模的安装技术、独特的滑模牵引技术、混凝土施工技术和工艺方法、斜井混凝土施工安全技术等,为以后的同类型斜井衬砌混凝土施工提供借鉴。     

天荒坪抽水蓄能电站上游输水斜井混凝土衬砌滑模施工与监理

本文介绍了天荒坪抽水蓄能电站上游输水斜井混凝土衬砌滑模系统、施工方法、施工情况及监理工作。     

XHM—7型斜井滑模

斜井滑模工程是天荒坪抽水蓄能电站一项重要的招投标竞争项目，是斜井混凝土衬砌施工可以不间断连续滑升的新型滑模。滑模系统由轨道、滑模、液压爬升装置、安全保险设施和运输系统几大部分组成。经过施工实践，证明滑模的设计是成功的。     

连续式斜井滑模混凝土衬砌施工技术研究与应用

介绍水电第十四局在近20多年中采用滑模进行斜井混凝土浇筑的施工方法以及近几年在多个抽水蓄能电站进行斜井混凝土衬砌施工过程中进行的一系列改进。采用斜井滑模施工技术全断面1次浇筑成形斜井混凝土,整体成形效果好,混凝土表面光滑平整,无错台及施工缝,极大地提高了混凝土表面质量。     

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。     

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.