基于DFOS的船闸水工结构监测研究

基于分布式光纤感测(DFOS)在大型工程结构监测方面的技术优势,将其应用于船闸水工结构的安全健康监测中,运用以布里渊光时域分析(BOTDA)和布拉格光纤光栅(FBG)应变感测技术对船闸闸首和闸室结构在施工中的应力、应变过程进行了监测;运用以光时域反射(OTDR)和拉曼散射光纤感测技术为原理的ROTDR系统对船闸闸首底板浇筑过程中混凝土水化热的释放进行了监测,并由此对应变监测结果进行了温度补偿。根据监测结果,综合分析了混凝土水化热释放过程和上部荷载双重作用下船闸闸首结构内部混凝土和钢筋的应力、应变过程,并验证了分布式光纤感测技术在船闸等大型水工结构施工安全监测中的可行性。     

南水北调中线安全监测应用系统提升改造实践

正一、南水北调中线安全监测系统问题分析1.系统概述安全监测是获取南水北调工程实时工作性态的有效手段,对于保障南水北调中线工程的正常运行具有重要意义。南水北调中线干线工程具有空间跨度大、建筑物类型多、监测项目多和监测点基数大等特点,全线安全监测业务开展过程中,产生海量多类型的安全监测数据,通过信息化手段支撑安全监测是刚性需求。南水北调中线安全监测系统在此背景下应运而生。系统于2009年规划,2010年投入建设,对中线工程全线各类建筑物的施工、运行期温度、水位、渗压、位移、应力、应变、变形等项目进行了全面监测,     

三峡大坝安全监测自动化系统简介

三峡工程安全监测覆盖整个枢纽建筑物及基础,接入系统的变形、渗流、应力应变等监测点共计有2 153点。安全监测的特点是测点多、分布面广、传感器品种多、工作环境恶劣、监测数据量大。结构建设充分考虑上述特点,并结合当前计算机网络技术发展现状和趋势,考虑分期实施要求,安全监测自动化系统网络总体分为监测中心至采集站层和采集站层至DAU(数据采集站)两层。系统主要包括1个监测中心、5个数据采集站、61个数据采集单元区。系统的数据管理与分析软件采用面向对象的软件设计方法,达到功能完善、操作灵活、运行可靠、先进实用的目标。     

大悬挑结构钢平台支撑体系选型在施工措施上的应用

现代场馆建筑根据其功能和造型美观的需求,常采用大悬挑的手法。该类结构的特点是大跨度、大悬挑、施工荷载大、支撑体系安全风险大;而该类结构施工支撑体系常因结构限制制约施工措施手段,研究此类结构施工的支撑体系选型对于同类结构的施工有着非常现实的意义。成都大魔方演艺中心工程为框架剪力墙结构,大陀螺屋盖采用双正交空间钢桁架受力体系,长轴152米,短轴1481.工程概况     

钢丝绳布置形式对悬挑支撑体系受力性能的影响分析及其工程应用

随着经济的发展和为满足人们生产生活的需求，越来越多的异形结构被应用到工程中，其中大 悬挑结构是一种施工难度很大的结构形式。为了保证悬挑支持体系施工的安全性，钢丝绳作为一种安 全措施被广泛应用．为了研究钢丝绳集中布置与分开布置对悬挑支撑体系承载力的影响，以及在保持荷 载不变时，两种布置形式下最大位移值，建立了悬挑支撑体系有限元简化模型并进行了分析，分析发现 钢丝绳的布置形式对复杂悬挑支撑体系施工安全的重要性。同时对复杂悬挑支撑体系进行了方案设计 和模拟分析，并对特殊部位进行了特别处理，为实际工程施工方案的设计提供了理论基础。     

悬挑基础设计问题探讨

在建筑工程中,如何解决多层砖混结构的基础压基问题极其重要。本文所述悬挑基础设计,较好地解决了这一难题,完全能满足设计与施工要求,是处理压基问题的一种安全、经济的重要方法。     

乌东德电站地下主厂房永久安全监测系统布置初探

乌东德电站地下主厂房跨度大、高度高、地质条件复杂,洞室稳定及施工安全问题较突出。为确保电站建设和运行期安全,在乌东德电站地下主厂房布置永久安全监测系统。根据监测成果,分析了主厂房围岩浅深部的应力和位移变化情况,指导设计支护参数的动态调整和施工方案的过程调整,对下一步工作提出了相应的建议。     

悬挑系统结构计算方法及其在施工中的应用

小湾电站进水塔塔体顶部两侧悬挑牛腿混凝土,施工中采用了分层悬挑浇筑的方法.对悬挑浇筑系统的结构计算方法以及在施工中的注意事项进行了总结和探讨.     

某体育馆钢桁架屋盖卸载监测研究

由于大跨钢桁架屋盖结构在施工过程中的受力状态与成型后受力模型的差异,存在结构受力体系转换,需要特别留意其施工过程安全,以广州国际体育演艺中心体育馆大跨钢桁架屋盖结构为例,首先对演艺中心大跨屋盖结构的施工过程进行模拟,然后建立大跨钢桁架屋盖结构的施工过程的监测系统,获得大跨屋盖结构施工过程中关键点挠度和关键构件应变,保证...     

狮子山隧洞穿越F16活动断裂带结构防震抗震关键技术

狮子山引水隧洞直接穿越F16程海—宾川活动断裂带,为解决隧洞结构位错、挤压—卸荷大变形、断裂活化等地质问题,研究深埋、软岩围岩、高地应力和施工扰动对隧洞结构的影响,文章基于"建筑抗震韧性"的隧洞结构及防震抗震设计原则,提出了隧道穿越活动断裂带时,衬砌设计方案、围岩加固措施、施工监测方法以及永久监控系统等一系列防震抗震关键技术,为高效优质完成施工任务及确保运营过程中的安全提供了技术支撑.     

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。     

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。