云南省祥云县许长水库除险加固方案优化研究

目前病险水库存在着一系列安全问题,不仅影响着大坝自身安全,也是对水资源的浪费,因此对病险水库进行除险加固是非常重要的.本文结合祥云县许长水库基本情况,运用灰色关联度评价方法,对大坝工程方案、帷幕灌浆工程方案、溢洪道改造工程、临时工程及其他工程方案等大坝除险加固方案进行了优化,得出具有可操作性的施工方案,通过实际施工与评...     

基于风险的病险水库除险加固方案优化技术

目前病险水库的除险加固设计只偏重于工程治理措施,倾向于水库大坝工程的安全,未考虑除险加固设计方案对下游居民安全、社会经济、城镇交通等的风险以及对自然环境的影响。因此,基于风险分析的除险加固优化技术对于今后病险水库除险加固方案是有效和必要的。本文参考国外病险水库大坝安全和除险加固风险分析理论的最新进展,结合我国病险水库大坝和除险加固技术的特点,进行了除险加固方案与大坝风险关联分析与决策、除险加固方案评价指标分析和基于风险分析的除险加固方案优化技术的研究,提出了基于风险的病险水库除险加固方案的评价、分析和优化方法,为今后病险水库除险加固工作提供技术支撑。     

基于多目标决策的病险水库大坝加固施工方案优化研究

为了更好地加固治理病险水库，针对加固方案决策，提出一种多目标决策方法，该方法引入AHP-EM组合赋权法。首先收集病险水库大坝加固方案的决策指标，采用AHP-EM组合赋权法进行组合权重赋予，以此来评价决策方案可行性。结果显示，在多方案评价中，从研究所选取的多个指标中选出最优方案，并对最优方案进行仿真和应用测试：仿真显示研究选取方案能够显著降低大坝孔隙压力，应用显示能够将大坝的垂直位移降低至0.026m。研究表明，多目标决策能够选出病险水库大坝加固的最优施工方案，在病险水库大坝加固和长期治理中具有重要作用。     

大坝修复成本预算

目前,美国高危病险坝的数量在持续增加,从大坝运行的安全角度从发,美国国际大坝安全协会组织了一次大坝安全评估,并提出了大坝修复成本预算报告。评估报告表明,修复和改造美国非联邦政府拥有的大坝大约需要500亿美元。     

除险文溪水库大坝安全评价及加固方案分析

由于文溪水库存在下游坝坡出现散浸现象,坝坡稳定安全系数不能满足规范要求,溢洪道砌体勾缝老化脱落等诸多病险问题,被鉴定为＂三类坝＂,文章针对文溪水库大坝安全现状及安全评价,分析并提出了大坝防渗、溢洪道改线、输水隧洞改造等加固技术方案。     

梅山水库大坝病险期间安全管理存在的问题及对策

梅山水库大坝已于2002年4月被鉴定为三类病险坝，在除险加固实施之前，应进一步加强大坝的安全管理，确保安全运行。主要讨论梅山水库大坝病险期间的安全管理情况以及存在的问题，并提出了改进的对策。     

金沙水库改建方案比选

介绍了金沙水库的基本情况,针对大坝安全鉴定中发现的问题,提出了金沙水库改造过程中前后两套不同的设计方案,通过对方案的比较分析,总结出在病险小水库工程的改造设计中,应注意针对现状水工建筑物的特点和型式进行设计,重视工程总体设计,采取科学合理的工程措施等问题。     

水库大坝漏水处理方法介绍

水库大坝漏水处理方法介绍叶和登（金华市水电局）水库大坝漏水对土石坝工程是较为普遍的现象，据我市统计因大坝严重漏水被列为病险库的约占全部病险库的４５％。这给工程安全运行带来不利，影响大坝安全，甚至造成垮坝失事，兰溪市海螺水库垮坝失事就是一例。土石坝漏水...     

水库大坝安全保障关键技术

本文系统探讨了我国水库大坝病险与溃坝规律。介绍了世界最高实体坝现场溃坝试验和室内试验结果,揭示了土石坝溃决机理和溃决过程。系统阐述了基于风险的大坝安全评价方法、病险水库除险加固技术、大坝风险控制非工程措施、大坝安全信息监测与预测预警、大坝风险标准等涉及水库大坝安全保障体系建设的一系列关键技术。本研究成果丰富了溃坝理论,完善了溃坝模拟技术,可服务于全国水库大坝安全行业管理和实践。     

病险水库除险加固方案优化技术的研究

目前,水库大坝工程安全以及工程治理措施为病险水库除险加固设计的主要侧重点,而对于自然环境、城镇交通、社会经济以及下游居民安全的影响分析较少。鉴于此,结合国内外水库除险加固风险分析理论以及水库大坝安全的最新进展,探讨分析了除险加固方与水库风险的关联决策;通过对事件树法与层次分析法的分析提出水库除险加固方案评价方法、优化技术,可为提高水利工程投入运行服役寿命和病险水库工程质量提供技术支撑。     

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.     

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。