涵内套管法在从化某水库除险加固工程中的应用

输水涵管作为水库枢纽"三大建筑物"之一,大部分穿坝而过,一旦出现隐患将直接危及大坝安全.涵内套管是一种施工便捷、经济实用、安全可靠的方法,中小型水库多凭工程经验进行套管加固.就此结合从化某水库除险加固工程,分析其过流能力和结构内力,并对内套钢管直径、厚度、原涵管加固、新旧管结合面处理等进行设计,如此可有效消除原涵管存在...     

水库放水涵管除险加固的处理

开平市现有小（I）型以上水库38座，由于历史等各方面的原因，普遍存在设计标准偏低、工程质量差、不安全隐患多。特别是水库放水涵管，伸缩缝止水锌片损坏、沥青老化、管身沉陷开裂、漏水严重等工程隐患。如不及早进行除险加固处理，势必危及土坝安全，其后果将不堪设想。对此，开平市针对现有水库放水涵管存在工程安全隐患，进行有效的内套钢管和灌浆加固处理。经多年运用检验证明效果良好，各水库均能安全正常运行，工程效益十分显。     

小管径涵管分节套管加固的设计与施工

在小管径大坝放水涵管工程加固中，采用一种新的套管方法，内衬钢管不焊接，用外包套管连接，使钢管能在小角度内转动，再通过灌浆方法填充管壁。对于涵管伸缩节局部错位、部分弯曲等问题，都能进行加固，在直径800?mm以下涵管加固工程中，能收到很好的经济效益和工程效益。     

大坝涵管防渗加固施工分析

结合江西赣州大坝3#坝工程施工实践，讨论了大坝涵管防渗加固施工中存在的常见问题。3#坝下涵管进口段位于残坡积土层中，加固工程是施工管理难点。涵管两侧和管顶需进行防渗墙造孔，涵管底部以及周围上、下游范围内加设帷幕灌浆处理，施工时需严格保证坝下涵管不受破坏，对施工中出现的难点和问题进行剖析并提出建议，为同类工程提供了参考。     

白礤水库输水涵管除险加固处理方案选择

白礤水库斜卧式输水涵管老化,洞身漏水严重,危及土坝安全.通过对输水涵管的除险加固设计,采用顶管的施工方法,消除安全隐患,确保工程安全运行.     

浅谈土石坝输水涵管安全隐患及处理措施

土石坝输水涵管存在隐患是影响水库大坝安全运行的重要因素之一,文章简要分析了土石坝穿坝输水涵管存在的问题,并总结湘西自治州近十几年来在水库除险加固中对土石坝穿坝输水涵管的处理经验,对同类工程隐患的治理有所参考。     

虹吸式放水涵管技术在合门水库除险加固中的应用

涵管改造往往是小型水库除险加固的关键环节,合门水库用虹吸式放水涵管取代原有隐患严重的坝底涵管,具有结构简单、施工方便、节约工期、节省投资、运行安全、管理方便等优点,为同类工程坝下涵管改造提供了成功的经验,对点多面广的小型水库除险加固具有一定的指导意义。     

许岙水库坝内涵管漏水处理方案设计

许岙水库位于瑞安市曹村镇许岙村,为小(2)型水库.2003年在全市水库安全普查中,该水库被确定为病险水库,同年实施了除险加固处理设计.介绍了对该水库坝内涵管漏水处理方案的设计.     

虹吸管在小型水库泄水涵管改造中的应用

杭州市萧山区89座需除险加固的小型水库,由于坝底涵管分别采用竹筋混凝土涵管、陶瓷涵管、三合土涵管和混凝土涵管,且多数涵管出现管身裂缝和渗漏现象,已成为大坝的严重隐患,需要进行改造.本文对涵管更新改造方案的选择,虹吸管的设计、施工和质量控制等进行了介绍.虹吸管己在2/3的需除险加固的小型水库中安装使用,使用结果表明,虹吸管不仅运行安全可靠,而且节约投资,经济效益十分显著.     

双泉水库输水涵管安全检测与裂缝修补

为了查明涵管的破坏情况和漏水原因，对涵管进行全面检测和安全分析，针对产生裂缝的原因，选择了高效，经济，可行的方案进行了修补加固，经过放水发电后的量水检测，修补获得了成功。     

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。