沥青混凝土心墙在东林水库工程的应用

东林水库位于吉林省嘎呀河下游．其功能主要是为石砚造纸厂枯水期供水．大坝为沥青混凝土心墙上石混合坝，最大坝高37m．坝顶长277m，水库总工程量为62．2万m’，其中混凝土为己5万m‘，工程总造价1300万元．现工程已竣工并运行了3年，实践证明质量良好，发挥了很大效益．以下将沥青混凝心墙的选用，以及该墙的设计与施工介绍如下．l沥青混凝土心墙的选用东林水库大坝原设计为浆砌石重力坝，后因资金和原材料等因素，改为土石混合坝，并决定采用灌注式沥青混凝土作防渗心墙，其具有以下优点．（l）建筑材料以当地石碴为主，另外采用一部分砂…     

浇筑式沥青混凝土心墙施工方法及质量控制探讨

麦海因水库位于新疆塔城地区额敏县境内,工程等别Ⅲ等,工程规模为中型,主要由沥青心墙砂砾石坝、导流放水涵洞、溢洪道等组成。麦海因大坝为浇筑式沥青混凝土心墙坝,坝体防渗体采用沥青混凝土,心墙底部扩大段接帷幕部分采用灌浆的垂直防渗式施工方案。文章对浇筑式沥清混凝土心墙的施工进行分析,具体包括沥青混凝土原材选择、沥青混凝土搅拌、沥青混凝土心墙浇筑及质量控制等内容。     

尼尔基水利枢纽坝体防渗工程分析

尼尔基水利枢纽工程在设计阶段曾对主坝、左右副坝拟定了3种防渗形式进行比选,最后确定了主坝为沥青混凝土心墙坝,副坝为粘土心墙坝的坝体防渗方案。经防渗监测表明：沥青混凝土心墙和粘土心墙的防渗效果良好,运行正常,满足规范要求。同时。在沥青混凝土心墙施工中作了技术改进,对碾压式沥青混凝土心墙和粘土心墙在低温条件下施工进行了研究和探讨。     

尼尔基主坝振捣式沥青混凝土心墙施工技术

尼尔基水利枢纽工程主坝结构形式为沥青混凝土心墙砂砾石坝。其中，沥青混凝土心墙部分采用了振捣式施工技术，克服了以往浇筑式沥青混凝土的分层离析问题，保证了沥青混凝土防渗心墙的整体均匀性．达到了既能满足设计要求又能省工省料的最佳效果.     

碾压式沥青混凝土心墙施工的温度控制

碾压式沥青混凝土防渗心墙的质量是评价沥青混凝土心墙土石坝工程防渗效果的最重要依据。热性施工的沥青混凝土温度控制是极其关键的质量控制环节；施工中如何有效地实施温度控制是确保防渗心墙施工质量的关键。本文主要介绍三峡茅坪溪土石坝沥青混凝土心墙施工温度控制的方法。     

尼尔基主坝碾压式沥青混凝土心墙施工技术

以尼尔基水利枢纽砂砾石坝工程中的碾压沥青混凝土心墙机械化施工为主题,以工程质量控制为核心,对碾压式沥青混凝土心墙原材料的选择及其性能、沥青混凝土配合比确定、沥青混凝土心墙施工工艺、施工机械设备、施工过程质量控制等进行了阐述.实践表明,碾压式沥青混凝土心墙与土料防渗体相比,具有防渗性能好、适应应变能力强、工程量小、施工速度快、节省工程造价等特点.     

茅坪溪土石坝沥青混凝土心墙机械化施工

茅坪溪防护土石坝沥青混凝土防渗心墙采用全过程机械化施工 ,这在国内为首例。目前国内建造高的沥青混凝土心墙经验不足 ,又缺少施工机械和专业施工队伍。对茅坪溪防护土石坝沥青混凝土心墙的施工进行了介绍 ,为类似工程提供了借鉴。     

金平水电站坝型比选研究

根据金平水电站坝址的水文气象和地形地质条件等基本资料,对砾石土心墙堆石坝和沥青混凝土心墙堆石坝进行技术经济比较。沥青混凝土心墙堆石坝防渗土料工程量小,施工环节少,占用土地少,环境影响小,施工技术成熟,工程投资省745万元,故采用了沥青混凝土心墙堆石坝方案,金平水电站已投产发电,运行良好。     

碾压式沥青混凝土心墙堆石坝填筑质量控制

沥青混凝土心墙作为土石坝的一种防渗结构,具有防渗效果好、施工便捷等诸多优点,沥青混凝土心墙坝型在我国应用越来越广泛,该坝型填筑的质量控制至关重要。文章主要结合工程实例,分析了沥青混凝土心墙堆石坝施工的质量控制体系,并探讨了如何开展沥青混凝土心墙堆石坝填筑现场施工质量控制,对大坝填筑质量控制要点进行了总结分析,希望可以为碾压式沥青混凝土心墙堆石坝施工技术人员提供相应的参考。     

碾压式沥青混凝土心墙快速高效施工技术探析

碾压式沥青混凝土防渗心墙作为防渗结构,具有结构简单、工程量小、防渗性能安全可靠等优点。但碾压式沥青心墙作为防渗体的施工经验还不很成熟,特别是土石坝碾压式沥青混凝土心墙施工,沥青混合料铺筑层厚一般为25cm左右,允许施工的环境气温日平均气温都在5℃以上,日降雨量小于5mm,全年碾压式沥青混凝土施工天数很有限,高寒多雨地区尤为突出,严重制约着土石坝沥青心墙的施工进度。本文介绍了以上特殊条件地区碾压式沥青混凝土快速高效施工技术,对同类型工程施工有一定的借鉴意义。     

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。