大卜冲水库坝址坝型方案比选

结合大卜冲水库工程的地形、地质条件,对两个坝址进行初选。在上、下坝址及坝型进行综合比选后,推荐上坝址混凝土重力坝方案。对重力坝的泄流型式及消能防冲方案进行比选后,溢流坝采用36 m无闸控溢流净宽方案,消能采用底流消能方案。水库枢纽建筑物主要由拦河坝、引水系统等建筑物组成。根据工程实际情况,对溢洪的方案进行比选,并介绍了工程总布置的设计。     

奋斗水库工程总布置方案

奋斗水库工程是以城镇供水为主、结合防洪、兼顾灌溉和发电等综合利用的工程。枢纽由拦河坝、泄水建筑物、取水建筑物、发电建筑物、输鱼建筑物等工程组成。枢纽总体布置是在选定坝轴线、坝型的基础上,选定其他建筑物的型式进行最终枢纽布置,合理地选择枢纽中各个建筑物的相对位置。文章根据地形、地质情况,从工程布局、施工、运行、工程量及投资等多个方面进行论述、比对,确定奋斗水库工程的总体布置。     

关坎脚水库大坝坝型设计方案分析

为得到贵州省湄潭县关坎脚水库工程适合的坝型,在深入分析坝线、坝型选择过程的基础上,提出采用碾压混凝土重力坝与混凝土面板堆石坝两个方案进行同精度设计,从枢纽布置、施工组织设计、工程投资等多方面对两种坝型枢纽布置建筑物进行综合比较,基于安全、经济的原则,最终确定推荐碾压混凝土重力坝坝型枢纽布置方案.研究内容可为同类工程设计...     

瓦村水电站工程建设方案比选

结合瓦村水电站工程地形、地质条件,对上、下坝址及坝型进行综合比选后,推荐下坝址混凝土重力坝方案,枢纽主要建筑物由拦河坝、发电厂房、左岸两级垂直升船机及交通道路等组成。根据工程实际情况,对工程总布置进行设计介绍。     

吉沙水电站首部枢纽拦河坝设计

吉沙水电站枢纽工程由首部枢纽、左岸有压引水隧洞、调压井、高压管道和地面发电厂房等主要建筑物组成。首部枢纽主要建筑物由拦河坝和电站进水口组成,拦河坝为混凝土重力坝。介绍了拦河坝、坝基处理和枢纽区边坡的设计情况。工程实际运行表明,首部枢纽拦河坝设计方案合理,可为在河道狭窄、边坡陡峻的河流上建设的水利水电工程提供参考。     

SETH水利枢纽泄水建筑物设计

SETH水利枢纽位于山区，是典型的综合利用水库，拦河坝为碾压混凝土重力坝，枢纽任务的实现通过功能坝段集于坝体一身，泄水建筑物不仅受地形地质条件影响，还受坝体整体布置的制约，具有布置较难、水头高、流速大、运用复杂等特点。通过对工程开发任务、调度运行情况的分析，根据坝型和地形地质条件，对泄水建筑物的布置、型式等进行了设计研究。遵循泄水顺畅的原则，将泄水建筑物布置于主河床靠左岸部位，利用一个表孔和一个底孔泄水。通过计算满足工程泄洪等各项工程要求，运行安全。本工程（坝高70 m级的碾压混凝土重力坝）泄水建筑物的设计与研究，对新疆地区类似工程的设计有较好的借鉴作用。     

东边水库施工组织方案分析

东边水库是一座以防洪、灌溉为主,兼顾养渔等综合利用功能的中型水库。该水库位于克音河支流双岔河右支叉上,现隶属于海伦市管辖。东边水库为中型水库,拦河坝为Ⅲ级建筑物。文章根据东边水库工程的地形地质条件、河流特点、枢纽工程布置,对东边水库工程导流方案选择进行分析。     

戈兰滩水电站工程大坝稳定分析

戈兰滩水电站的工程等别为二等,工程规模为大(Ⅱ)型,主要建筑物包括挡水、泄水及消能建筑物、发电引水系统和电站厂房等,主要建筑物拦河坝等按2级建筑物设计.工程采用RCC重力坝,拦河坝由左岸挡水坝段、溢流坝段、右岸挡水坝段组成,最大坝高为113 m,坝顶总长为466 m,共分为16个坝段.根据枢纽布置特点和剖面设计,对每个坝段均进行了坝基稳定和应力分析.     

浅析荔波县拉寨水库枢纽坝型比选

结合荔波县拉寨水库枢纽概况,根据选定的下坝址水文、地形及地质条件,坝型选择了重力坝和钢筋混凝土面板堆石坝坝型进行比选,从工程地质条件的适宜性、建筑物布置、施工条件等技术经济方面进行比选,最终选择重力坝方案,施工技术简便,布设紧凑,经济性较高。     

崖羊山水电站枢纽布置优化简介

崖羊山水电站枢纽布置优化，主要对比了不同的坝址及坝形，选定较优的布置方案；整个枢纽布置的主要建筑物有拦河坝、泄水建筑物、引水发电建筑物、冲沙建筑物等。     

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.