新疆某水电站工程料源规划

由于料场天然开采混凝土骨料获得率较低,对天然料场人工破碎补偿混凝土骨料方案与洞渣料人工破碎方案、天然料人工破碎加洞渣料人工破碎方案与天然料场人工破碎补偿混凝土骨料方案进行经济比选,综合考虑占地弃渣等因素,选择合理料场开采。     

乌东德水电站混凝土人工骨料料源选择

乌东德水电站工程规模巨大,混凝土全部采用人工骨料。为保证工程建设的顺利进行,需要寻找综合条件较好的人工骨料料源。在初查的基础上,选择条件较好的乌东德坝址开挖料、施期料场、观音岩料场、马鹿塘料场作进一步详查。经多方面综合比较,最终选择坝址地下工程开挖料和施期料场石料的组合料源方案,其岩性以灰岩、白云岩为主,储量和质量均能满足工程要求。为保证大坝混凝土施工质量,大坝混凝土人工骨料全部采用施期料场灰岩,不采用坝址工程开挖料。介绍了料源选择过程,可供同类工程施工设计参考。     

鲁地拉水电站混凝土骨料料源选择研究

鲁地拉水电站混凝土工程量大,骨料料源有灰岩料场、砂岩料场、正长岩料场以及开挖碴料,开挖碴料又分为砂岩、正长岩2种,骨料料源复杂。通过对不同类型的骨料料源进行综合技术经济比较,最终选择以砂岩开挖碴料加工碾压混凝土粗骨料、以料场开采的正长岩为主加工碾压混凝土细骨料及常态混凝土粗、细骨料的方案。     

溪洛渡水电站混凝土骨料料源选择

溪洛渡水电站混凝土工程量巨大,骨料料源有天然砂石料、灰岩料场、玄武岩料场以及开挖碴料,通过对不同的料源以及各料源的组合方案进行技术经济比较,最终选择了玄武岩开挖碴料作为大坝混凝土粗骨料、地下洞室粗、细骨料,选择大戏厂灰岩料场作为大坝混凝土细骨料。     

孟底沟水电站工程混凝土骨料料源选择

孟底沟水电站混凝土全部采用人工骨料。经综合比较,选择杨家坪石料场开采料、主体工程石方开挖料的组合料源方案,以上料源储量、质量均满足要求。文章根据孟底沟水电站工程特点和实际情况,提出了混凝土骨料料源选择、砂石加工系统布置设计方案。     

伊江上游施工电源电站小型砂石系统设置

在缅甸的施工电源电站引水线路较长,工地较为分散,在综合考虑料源、开采运输费用、砂石骨料总需要量等因素的情况下,最终选择在2号、3号洞及厂房附近恩梅开江岸边分别设置一个小型砂石系统满足隧洞衬砌混凝土及厂房混凝土浇筑时骨料需求,其中2号、3号洞砂石系统利用开挖洞渣料作为毛料,厂区砂石系统料场为河滩料场。     

乌东德水电站工程施期料场优化分析研究

作为乌东德大坝混凝土的唯一料源,乌东德水电站工程施期料场的真实储备和开采系数,关系到整个枢纽工程混凝土砂石骨料的供应。在工程实施阶段,施期料场白云岩储量与规划方案存在一定差异,且洞挖料利用率偏低。为满足工程需求,对大坝混凝土骨料原岩总需求、地下洞室实际可利用料量进行复核,以此开展施期料场开采量分析优化和白云岩毛料堆存方案优化,并对可能面对的风险进行了分析,提出了应对策略。     

混凝土骨料料源选择与开采设计——以白河水电站为例

白河水电站的混凝土骨料料源有3类,分别为工程开挖料、天然砂砾石料及人工开采块石料。为降低工程造价、减少工程弃渣及保护周边环境,料源优先选择满足要求的工程开挖料,不足部分从规划的天然砂砾石料场中择优选取。工程采用分期导流,工期受汉江洪水影响较大,为保证混凝土浇筑进度,必须做好料场的开采、备料计划,制定安全、可行的开采方案。     

龙开口水电站白云岩混凝土骨料料源选择和加工运输方案研究

龙开口水电站通过拟选骨料料源的试验研究和技术经济比较,选择燕子崖料场白云岩作为混凝土骨料料源,并根据料场的开采条件、料源岩性、砂石加工系统与混凝土生产系统的布置及交通条件,选定了骨料生产工艺、半成品垂直运输方案和成品骨料长胶带运输方案.     

AETS水利枢纽工程混凝土骨料场选择与平衡分析

AETS水利枢纽工程混凝土需用量大,骨料单价对工程投资影响较大,料场选择及开采方式对工程施工尤为重要。以物理试验数据为依据,根据工程区砂砾料的基本情况,充分考虑施工开采影响,对开采时间、截流淹没影响等因素综合进行分析对比,得出工程区施工采用C2、C3、C4料场作为混凝土骨料较为合适;对枢纽区混凝土骨料采用料场天然筛分+超径石破碎补偿和利用开挖料破碎加工两个方案也进行分析对比,得出充分利用开挖料结合料场开采超径石的方式为最优方案。可为后期料场比选提供理论依据。     

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。