后湾水库除险加固实践

后湾水库枢纽建筑物大坝、溢洪道、输水洞等存在不同程度的安全隐患,为确保水库工程运行安全,必须对水库工程进行除险加固。通过分析,提出了对大坝下游加固培厚、坝体防渗处理、溢洪道补建、输水洞钢衬、重建进水塔等除险加固措施,以保证水库安全。     

磨掌水库除险加固改造方案比选与工程设计

介绍了磨掌水库工程概况,经对水库进行蓄水安全专项检查发现,大坝坝体、溢洪道及输水洞存在安全隐患,直接影响水库稳定运行,为此必须对水库进行除险加固。通过加固方案比选,确定了最佳方案,并对水库大坝、溢洪道及输水洞进行了设计。     

花古水库南、北副坝及输水洞工程地质条件及评价

提出了花古水库坝坝体及南、北输水洞存在的问题,对南、北副坝工程及南、北输水洞工程地质条件进行了评价,旨在为相关工程提供参考。     

漳源水库输水洞应急除险加固优化设计

漳源水库输水洞由于运行时间较长,洞身外部回填碾压不密实,渗漏水严重,坝体安全存在较大隐患.对输水洞应急除险加固的各个方案,从经济、技术方面进行比选,确定了最优方案,经实际运行证明,该方案切实可行.     

禹门口提水东扩工程西梁水库工程地质特征

西梁水库位于山西省浍河的支流上，是一座小型水库，始建于20世纪50年代，由于年久失修，溢洪道及输水涵洞皆已废弃。为了使水库在禹门口提水东扩工程发挥更安全作用及经济效益，需要对水库除险加固、对大坝加高培厚。文中分析了坝址，溢洪道、输水洞的工程地质条件，进行了工程地质评价，此外还对坝体质量进行了评价。     

阳坡水库输水洞加固设计简述

介绍了阳坡水库工程概况,简述了输水洞现状和工程地质条件,通过分析阳坡水库输水洞存在的安全问题,对输水洞进行了加固设计,解决了涵洞洞身漏水严重、强度较低等问题,消除了阳坡水库的重大安全隐患.     

关于水库输水洞维修加固设计初步分析

输水洞承担灌溉任务,是主要的永久建筑物,其工程级别为3级。输水洞进口翼墙处出现多处裂缝,混凝土脱落现象严重,有必要进行加固处理。文章结合拉马章水库输水洞维修加固工程案例,提出输水洞维修加固设计方案,并对其进行分析。     

亮甲山水库输水洞堰闸出流公式分析率定

本文通过分析对除险加固改造后的亮甲山水库输水洞出流流态进行了确定,其出流流态为自由孔流;根据实测流量资料对输水洞自由式孔流出流经验公式进行了分析,当启闭高小于等于0.17 m时,输水洞出流量采用公式:Q=(0.60-0.176e/hu)be 2ghu~(1/2)推流;当启闭高大于0.17 m小于等于0.35 m时,输水洞出流量采用公式:Q=(0.67-0.176e/hu)be 2ghu~(1/2)推流,能满足水库防汛抗旱和水文资料整编要求。     

民主水库除险加固优化设计分析

以民主水库设计除险加固方案为例,首先分析了该水库主要存在的问题,在此基础上对水库的调洪演算、坝顶超高、坝顶高程等进行了验算,选择合适坝顶高程,并采用帷幕注浆技术对坝体进行了加固,采用软件对其稳定性进行了验算,然后对输水洞、溢洪道等关键部位进行了优化设计,取得了良好的加固效果。     

高压旋喷灌浆技术在构筑输水洞截流环墙中的应用

采用高压旋喷灌浆技术构筑连环水泥桩，形成输水洞外截流环墙，治理 洞身与坝体之间接触渗漏，阻截渗流，此方法经黄前水库输水洞实践证明是成功 的，具有在同类工程中推广应用价值     

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。     

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。