水库碾压混凝土重力坝设计要点研究

针对目前水库大坝进行碾压混凝土重力坝设计过程中出现的问题影响,文章以实际工程项目为例,分析了碾压混凝土重力坝布置,并提出了碾压混凝土重力坝设计要点,其目的是为相关建设者提供一些理论依据。结果表明,要想提高水库碾压混凝土重力坝设计的科学合理性,需结合工程项目的实际情况,来保证重力坝预制构件、钻孔与温控简化的作用效果。     

盘县卡河水库碾压混凝土重力坝设计分析

文章结合盘县卡河水库分析工程设计方法,以该工程的碾压混凝土重力坝设计为重点,论述了工程结构布置方案,并对重力坝的设计方法进行了探究。     

高碾压混凝土重力坝渗流分析和防渗结构的研究

龙滩工程大坝是一座200m级的高碾压混凝土重力坝,由于库大水深,水库空库机会少,检修条件差,所以大坝上游面防渗结构的可靠性和耐久性是保证大坝安全运行的关键技术之一。“九五”国家科技攻关项目《高碾压混凝土重力坝渗流分析和防渗结构的研究》专题,系统地研究了碾压混凝土本体与层（缝）面的渗透特性,研究了一套能模拟大坝各种防渗设施及反映碾压混凝土坝渗流特点的计算方法,并设计研究出能供龙滩高RCC重力坝及类似工程使用的防渗设计方案。专题依托在建的江垭工程RCC重力坝（现已建成）和即将动工兴建的龙滩工程高RCC重力坝,使渗流分析和防渗结构的研究取得一大批创新性成果,并推荐了可供龙滩工程最后选用的防渗方案,这对于其他类似工程也有重要的借鉴意义。     

贵州省贵定县高粱坝水库碾压混凝土重力坝设计

粱坝水库碾压混凝土重力坝设计充分考虑碾压混凝土大仓面碾压、快速施工的特点,大坝结构及分区设计在施工中取得良好效果,可为类似的工程提供借鉴.     

通过阎王鼻子水库施工对碾压混凝土工艺适应性的分析

阎王鼻子水库设计为碾压混凝上重力坝，施工中由于闸墩较多，内外结构复杂，工程规模较小，设备配置杂而不足，使碾压混凝土经济快速的特点难以发挥，且碾压混凝土和常态混凝土施工交替频繁，导致进度缓慢，质量难以保证，因此类似阎王鼻子水库的重力坝不宜采用碾压混凝土工艺．     

王家洲水库碾压混凝土大坝质量控制要点浅析

在浦城县王家洲水库碾压混凝土重力坝施工过程中,结合自身工程特点,认真分析王家洲水库大坝碾压混凝土施工中容易出现质量问题的关键部位和薄弱环节,找出质量管控过程中需要注意的关键和要点,在碾压混凝土大坝施工过程中强化质量管理和控制,保证大坝碾压混凝土施工质量能够满足规范和设计要求。     

石膏山水库枢纽坝型方案设计比选

对石膏山水库枢纽坝型选择混凝土重力拱坝及碾压混凝土重力坝两种设计方案进行分析,根据所提供的基础资料,通过对两种枢纽坝型方案的分析、比较,最终确定了合理的坝型。     

人工砂中掺天然砂、粉砂在西溪水库工程中的试验和应用

西溪水库位于浙江宁海县黄坛镇，是一座以防洪、供水为主，结合灌溉、发电的综合利用工程。水库库容8500万m^3，电站装机6000kW，大坝为碾压混凝土重力坝，坝顶长249．50m，坝顶高程153．00m，最大坝高71m，坝顶宽7m，坝体为全断面碾压混凝土，混凝土方量约为30万m^3（含常态混凝土）。根据华东勘测设计院编制的《西溪水库工程碾压混凝土重力坝施工技术要求》，西溪水库工程碾压混凝土设计技术指标（见表1）。     

驮英水库坝型比较阶段的混凝土面板堆石坝设计

驮英水库拦河坝经混凝土面板堆石坝与碾压混凝土重力坝两种坝型的比选,推荐采用混凝土面板堆石坝坝型。根据地质地形情况对混凝土面板堆石坝、溢洪道、灌溉、发电系统等建筑物进行协调布置。结合坝料主要来源于料场和溢洪道开挖料的特点,对大坝进行了分区设计,并根据坝料室内试验及现场试验结果初步确定坝体填筑标准。     

关坎脚水库大坝坝型设计方案分析

为得到贵州省湄潭县关坎脚水库工程适合的坝型,在深入分析坝线、坝型选择过程的基础上,提出采用碾压混凝土重力坝与混凝土面板堆石坝两个方案进行同精度设计,从枢纽布置、施工组织设计、工程投资等多方面对两种坝型枢纽布置建筑物进行综合比较,基于安全、经济的原则,最终确定推荐碾压混凝土重力坝坝型枢纽布置方案.研究内容可为同类工程设计...     

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。     

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。