水利水电工程建筑物三维可视化建模技术研究

准确、快捷的创建水利工程三维可视化模型是切实促进工程现代化、数字化发展的关键举措,高效的建模技术是实现这一举措的主要工具。对于可视化技术而言,这是一种涉及众多知识和学科的新兴技术,从出现以来就得到了广泛的关注和应用。建模实现可视化可以使人们从图形等资料中直接接收相应的信息,比传统意义上的文本接受方式更加快捷、明了,此外在三维模型当中进行修改或更新也更加方便。     

基于OpenGL的涵洞三维可视化系统的研究

传统的涵洞二维设计与三维可视化分离,不能够直观地观察到三维模型的建立以及更新的过程。为了实现涵洞工程设计三维可视化表达,论文采用VC++6.0编程,基于MFC的OpenGL图形应用程序框架,开发了涵洞三维可视化系统。该系统通过参数化设计,应用图像处理技术,有效集成了建筑物方案设计、结构设计,将设计成果三维可视化。实例表明,该系统有别于传统的非集成化设计,为涵洞三维可视化设计提供新方法。更多还原     

烟囱在地震作用下可视化仿真系统开发

为直观形象的描述烟囱在地震作用下的结构破坏机理,提出建立烟囱在地震作用下的可视化仿真系统。该系统以VC++为平台,融合OpenGL图形技术,利用ANSYS软件生成的数据,通过对不同烟囱结构进行参数化建模,实现了在不同工况下烟囱地震动力特征图形三维可视化仿真。实例得出,在水平地震作用下能引起烟囱结构物上部破坏的结论。同时系统还具有查询不同烟囱的结构参数及任意截面在地震作用后的壁厚值的功能,为烟囱抗震设计及预测结构物的震害提供了直观依据。     

基于BIM+GIS的大坝安全监测信息可视化展示技术研究

为了解决传统大坝监测信息三维可视化程度低,展示不够直观、形象等问题,采用BIM+GIS技术,将监测信息展示从传统二维空间拓展到三维空间。对BIM建模、模型轻量化、三维可视化展示以及系统功能设计进行了研究,通过在桃源水电站的应用实例表明,BIM+GIS技术能够实现大坝安全监测信息三维可视化展示,展示效果更为形象、生动,具有广泛应用前景。     

可视化技术在土石方平衡系统中的应用与研究

介绍了如何在水布垭面板堆石坝土石方平衡系统中实现三维地形、施工方案、施工进度、施工过程可视化的技术;提出了利用真实场景实时绘制技术、实时建模技术和网络通信实现施工方案、施工过程等的可视化设计思想.在PC机上利用Performer和OpenGL编程开发了可视化子系统.该子系统真实地再现了三维坝区景观,并能按多种方式进行漫游,实现了坝体填筑、料场开挖的工程进度的查询和施工方案、施工过程的动态仿真,有助于工程设计与决策人员全面、准确地掌握施工状况,促进大型水电站工程的施工管理.     

大坝地震反应数据场三维动态可视方法

为了动态地显示大坝地震反应数据场的整体变化情况，本文提出了基于网络、表面、体绘制和多断面的数据场三维动态可视方法，可以立体地反映出三维数据场的整体数据分布，实现大规模数据场实时动态可视，使人们及时准确地了解大坝地震反应过程，正确地做出决策。可视化图形用VC6.0编程，并使用了OpenGL函数，在实现动态显示时，采用了连续帧显示技术。     

基于DEM的河道地形三维可视化研究

为了实现河道地形真实感显示,运用了DEM(数字化高程模型)数据格式中的三角网格模型,利用OpenGL提供的光照、材质、纹理映射,反走样等技术实现了河道地形的三维可视化,利用VC 及OpenGL中的平移、旋转、缩放等功能,实现了河道地形三维动态显示的效果.在添加了多种工况的洪水数据后,实现了河道流场可视化及防洪预测等相关功能.     

WebGIS及三维可视化技术在铜川新区供水管网中的应用研究

分析了当前供水管网管理信息系统中存在的两个主要问题———系统结构的不合理以及管网信息二维显示的局限性,为此就铜川新区的供水管网管理提出了一套基于WebGIS和三维可视化技术的解决方案,系统结构采用B/S模式,并利用MapXtreme实现了网络化,利用OpenGL技术实现了三维可视化。     

面向对象图形模型在水电工程中的应用研究

为了实现水电工程的实时动态可视化,基于面向对象图形建模技术,构造了三个层次的面向对象的图形模型(单元模型、工序模型、场景模型),提出了水电工程可视化系统的建模规则,并通过高效的面向对象图像渲染引擎、施工仿真系统和数据库系统一起构建了水电工程动态可视化系统,为工程管理和决策者提供了直观、高效的可视化平台。     

基于CATIA的引水隧洞施工进度三维可视化研究

针对水电工程引水隧洞三维模型不能重复利用,并且三维建模与施工进度可视化展示平台不统一的不足,将CATIA引入引水隧洞施工进度三维可视化研究中,在其平台上实现隧洞施工进度三维可视化。关键技术包括参数化方法、设计过程模板化技术、知识工程设计表技术和二次开发技术,通过建立引水隧洞三维参数化模型与施工进度计划的关联,模拟施工过程。以某工程引水隧洞压力管道竖井为例,建立了基于CATIA的引水隧洞压力管道竖井三维参数化模型,并建立了三维模型与施工进度计划的关联,实现了隧洞施工进度三维可视化。结果表明,该研究实现了三维建模平台与施工进度可视化平台的统一,提高了施工进度可视化的效率,为施工进度计划的合理与高效制定提供了理论与技术支持。     

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。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

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.