科克塔斯水库泄洪洞水力学计算研究

科克塔斯水库泄洪洞位于坝体右岸,由导流洞改建而成。泄洪洞与导流洞在平面上为同一轴线,泄洪洞由引渠段、进口塔架段、洞身段、出口消能段组成。泄洪洞洞身段底坡变化复杂,水流变化复杂,文章结合科克塔斯水库泄洪洞的布置,对泄洪洞洞身段和出口消能段的水流情况进行了细致研究。     

积石峡水电站施工导流设计概述

积石峡水电站采用土石围堰一次拦断河床、大坝基坑全年施工、左岸隧洞过流的施工导流方式。主河床截流后枯水期导流洞单独泄流,汛期导流洞与泄洪排沙底孔联合泄流。该工程施工期的洪水流量选择充分利用了河段梯级上游龙头水库龙羊峡水电站的调洪控泄作用,导流洞下游段与中孔泄洪洞结合,且汛期利用泄洪排沙底孔参与导流,减小了导流建筑物规模,节约了工程投资,取得了较好的技术经济效益。     

钢模台车在隧洞渐变段中的运用

龙头石电站工程采用3条泄洪洞汛期泄洪3,条泄洪洞均布置在电站左岸,采用无压泄洪3,#泄洪洞进口段100 m设计为渐变段,渐变段顶拱与正常洞身段顶拱参数不变,隧洞宽度不变,隧洞边墙由12 m渐变至14.5 m。渐变段混凝土采用全断面衬砌,衬砌厚度1.5 m。原施工方案中的边墙衬砌模板为悬臂模板、顶拱为承重架配散装组合钢模板。但由于进口塌方影响,渐变段隧洞浇筑工期若按原方案施工则无法满足度汛要求。为了保证安全度汛及隧洞泄洪运行安全,采用了钢模台车浇筑渐变段施工技术,保证了工程安全度汛。     

楼庄子水库工程溢洪洞的水力计算

楼庄子水库是头屯河上游山区控制性骨干工程,其主要任务是灌溉、防洪和城市生活及工业供水,是一座综合利用的水库枢纽工程。溢洪洞为楼庄子水库工程的主要泄洪建筑物,通过对其进口控制段、无压洞身段及出口消能段的水力计算,分析了溢洪洞的结构布置、进出口尺寸等设计要求及水力特性。计算结果表明,本工程溢洪洞泄流能力满足规范要求且流态较好,可为类似工程提供一定参考。     

津桥湖泄水库洪洞出口边坡开挖稳定性分析

津桥湖水库泄洪洞出口边坡开挖受限,须采取陡边坡开挖,存在较大安全隐患。因此,本文主要针对该问题,采用有限元软件ANSYS对泄洪洞出口段建立三维模型,模拟计算泄洪洞出口边坡开挖应力、应变场,分析其稳定性。以上计算分析可为泄洪洞设计、施工及后期运行提供参考,具有较高工程价值。     

泽城西安水电站(二期)溢洪道挑流段开挖方案

泽城西安水电站(二期)工程溢洪道,布置于水库右岸大坝与泄洪洞之间的哑口内,进口位于大坝上游约200 m处,出口距大坝下游坝脚约1.5 km,由引渠段、闸室控制段、泄槽段、挑流消能段组成,总长300.31 m。文章介绍了溢洪道挑流段开挖工程的施工布置情况,阐述了爆破开挖的资源配置措施及石方明挖步骤,对爆破参数选定进行了推理计算,解决了质量、安全等问题。     

满拉工程导流泄洪洞开挖全断面贯通

西藏满拉水利枢纽是以灌溉、发电为主，“一江两河”地区综合开发的骨干工程。为减少施工期导流工程量，本枢纽采用导流洞与永久泄洪洞相结合的方式进行设计。本文系统地介绍了导流泄洪洞的结构布置、导流泄洪洞开挖等施工概况。     

新疆柳树沟水电站工程的导流兼泄洪洞设计

在新疆柳树沟水电站的工程设计中,为了节省临建工程量,适当地抬高了导流洞的进口高程,使导流洞与永久泄洪洞完全结合,兼顾施工导流与永久泄洪任务;导流洞一次建成过流,在下闸蓄水后仅对工作闸室和出口鼻坎进行局部改建。经水工模型试验模拟和详细设计研究,并经1年半时间的导流期过水验证和初期下闸蓄水的考验,均正常运行。目前,导流洞的改建基本结束,工程即将竣工。运行验证和监测资料表明,柳树沟水电站工程的导流兼泄洪洞是成功的设计案例,总体达到了优化枢纽布置和减少投资的目的。     

浅析溢洪道结构设计优化

南湃项目的溢洪道原设计为顺右岸冲沟曲线布置,由引渠、溢流堰、进口明渠、溢洪洞、出口明渠组成。因明渠底板高程较低、进出口明渠边坡开挖高度较高,从而使边坡开挖支护工程量较大。经优化后的溢洪道为直线,由进口段、洞身段和出口段组成,在满足使用功能和安全的前提下,减小了安全威胁,节约了工程成本。     

构皮滩水电站泄洪洞优化设计

构皮滩水电站为满足2008年12月工程提前发电的需要,结合现有泄洪洞地质情况和施工情况对泄洪洞布置进行了专题研究,结果表明利用降低进口高程为550 m的泄洪洞和坝身放空底孔联合参与后期导流,可缓解2007年导流隧洞下闸封堵后大坝在2008年汛期施工的压力,为大坝施工增加了2个月左右的工期。     

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。     

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.     

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。