丰满大坝维修加固可行性分析

本文分析了丰满大坝坝基和坝体的有利条件,指出大坝目前存在的问题是先天性缺陷造成的历史遗留问题,同时分析了近70年来坝体溶蚀、混凝土强度和F67断层的变化情况,提出了丰满大坝进行维修加固的可行性。同时指出维修加固重中之重要解决的问题是上游面A块渗漏问题,遏制渗漏可消除对混凝土耐久性的不利影响和泄洪安全隐患。按照近70年运行实践,可以预见防渗加固的同时采取综合措施解决其它问题后,可保证丰满大坝的长期安全运行：     

丰满水电站坝体混凝土质量分析

丰满大坝由于历史原因存在先天性缺陷,虽经多次补强加固,但问题未能得到根本上解决。通过综合分析加固改造工程效果及近年来的混凝土调查现状,分析了丰满大坝坝体混凝土目前存在的主要问题。     

丰满大坝坝顶抬高观测与分析

丰满大坝坝顶垂直位移的测点在６０年代发现有逐年抬高现象，经过观测资料的分析，摸清了坝顶抬高的变化规律。经过大坝的筑坝材料、混凝土质量、地基地质、坝体混凝土的碱集料反应、坝体温度等温度、试验与分析，掌握了坝顶抬高的原因，为丰满大坝加固工程和安全运用提供了依据。     

丰满大坝加固工程钢筋混凝土护面对坝体抗震作用

丰满大坝是我国最老的大型混凝土重力坝，地震设计烈度为8度，由于大坝施工质量差，存在着混凝土强度低、稳定性能差等问题．对此，在大坝加固设计中，为提高大坝抗震能力，提出了在坝体表面做一层钢筋混凝土护面，护面厚度为1.0m，护面混凝土标号为R300，布设φ20螺纹钢筋网，保护层厚为40cm     

坊芦河水库大坝改造工程施工方案选择

分析了吃芦河水库大坝存在的问题，从坝体增厚、坝面护坡、加宽坝项增设防浪墙三方面论述了大坝除险加固措施，并从反滤填筑和棱体堆砌、坝体土方填筑、坝面混凝土预制块预制和砌筑防浪墙和坝顶公路混凝土浇筑几个方面对质量控制进行了论述。     

陈村水电站大坝安全管理工作概述

陈村水电站所属的陈村，纪村两座梯级大坝，均因历史原因而存在比较严重的缺陷，在首轮大坝安全定检之前即已进行了一系列补强加固工作。通过首轮定检，进一步查明了两座大坝的主要安全问题，其中陈村大坝被评定为“病坝”。针对陈村大坝存在的坝体裂缝多，大坝下游面１０５ｍ高程裂缝已造成坝体局部破损等问题，电站与主管局及科研院所共同分析研究，采取措施，完成了大坝的补强加固工作。     

对丰满大坝全面维修加固方案的建议

丰满大坝全面加固工程设计工作复杂,特别是构筑坝体抗渗体系的方案难于确定。本文对比了坝体混凝土现状与规范要求的差异,探讨了灌浆帷幕合格标准,提出了灌浆＋排水作为主要防渗措施的建议,同时建议大坝全面维修加固工程综合治理方案确定时考虑溢流坝段降渗工程已经取得的成果,重视新老混凝土结合,坝面抗冻保温和纵缝处混凝土效果的分析论证。     

丰满大坝加固与安全监测系统

由于丰满大坝建设期施工质量差异，存在很多严重缺陷。运行后，通过多次改建和加固，建立并逐渐完善了大坝安全监测系统，进行了大量的调查，试验研究工作，包括坝基地质勘探及试验、大坝抗震调查及试验、大坝混凝土性能调查及试验、大坝混凝土耐久性调查及试验，在对大坝恢复改建的基础上，运行期进行了大坝上，下游面补修，大坝防渗，预应力锚固等加固处理，针对运行中出现的问题又进行了溢流面抢修、上游面２２６．００￣２４５０     

关于改善丰满大坝观测的建议

丰满大坝加固即将完工，其仍存在整体性差、混凝土特低强、坝体扬压力高、冻胀开裂和老化等隐患，急需改善观测系统以指导下一步加固。根据该坝现有观测设施，提出以扬压、渗漏、纵缝与裂缝观测为主的改进建议     

中日丰满大坝修复加固计划调查

鉴于丰满大坝存在严重的缺陷和隐患，由日本国际协力事业团负责对大坝进行了详细调查、并从多方面对大坝进行了全面评价分析，提出了特种材料灌浆，坝体预应力锚固、水压钢管补修、增设排水孔和观测设施、库容曲线测量等８项应急措施，以及增设溢洪道、增强增坝稳定工程（基础断层坝段）和防止坝体冻融老化３项永久加固方案，对丰满大坝加固改造具有积极的指导意义。     

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。