双塔水库泄洪建筑物缺陷修补施工技术浅析

双塔水库1号溢洪道闸墩、闸底板、挑流消力坎破损严重,严重制约了水库泄水能力。通过分析缺陷原因,制定合理的修补技术方案,选择优质的缺陷修补材料,采用ECM环氧修补砂浆施工工艺,有效地防止了病害的继续扩大,延长了水工建筑物的使用寿命,消除了水库运行的安全隐患。     

防渗抗冲磨改性环氧砂浆在水利工程快速修复中的应用

奴尔水利施工枢纽的渠道修补工程具有工期短、施工环节复杂等特征，采用防渗抗冲磨砂浆来对工程渗漏部分进行修补，符合施工需求。文章结合奴尔水利施工枢纽对防渗抗冲磨改性环氧砂浆的实际应用及施工方案进行分析，通过水利工程运行检验，改性砂浆可以最大限度减少水利工程渗漏，确保该项目的施工质量。     

新安江厂房溢流面老环氧砂浆护面开裂状况的考察与分析

新安江水电站溢流面采用环氧砂浆进行裂缝修补已40年，是我国较早采用环氧砂浆进行修补的工程。本文对早期环氧砂浆修补薄层的开裂情况和特点进行了细致的现场考察和描述，并从断裂能的角度对裂缝进行了分类。结果表明，这一方法进行裂缝分类是可行的，裂缝外观及其断裂能的考察结果是一致的。     

环氧砂浆在大渡河龙头石水电站2#泄洪洞修补中的成功应用

通过环氧砂浆在龙头石水电站2#泄洪洞修补中的成功应用,总结了环氧砂浆在水工建筑物修补中的特性、施工工艺及流程。环氧砂浆在龙头石水电站修补中取得的成功,能够为今后类似工程提供一定参考。     

JME型改性环氧砂浆在泽雅水库泄洪洞钢衬修复工程中的应用

JME型改性环氧砂浆作为一种混凝土修补材料具有良好的抗冲磨特性,能有效地抵御高速水流对材料的剥蚀和高速水流中推移质修补层与原混凝土界面脱离。鉴于泽雅水库泄洪洞进口段钢衬受损严重和隧洞进口段流态特点,利用JME型改性环氧砂浆抹涂替代局部钢衬对隧洞进口段进行修复,运行中对泄洪洞进口段的检查未发现有剥落的JME改性环氧砂浆涂层,说明JME型改性环氧砂浆抗冲磨材料与混凝土粘结完好,达到预期的效果。     

环氧材料在毛尔盖水电站引水隧洞混凝土缺陷修补中的应用

将改性后的NE-Ⅱ型环氧砂浆和NE-Ⅲ型环氧胶泥,应用在毛尔盖水电站引水隧洞混凝土缺陷的修补处理施工,处理后引水隧洞运行良好。环氧材料的性能、施工方法及工艺流程、质量控制与质量检测等满足设计和技术规程要求。同时总结了环氧砂浆和环氧胶泥的应用效果。     

环氧砂浆热膨胀性能试验研究

环氧砂浆的热膨胀性能对其在水工建筑物修补中的应用效果有很大的影响。文章通过改变固化剂类型、砂胶比以及砂子类型等不同试验方法,对环氧砂浆的热膨胀性能进行了研究,分析了影响环氧砂浆热膨胀性能的主要因素。结果表明:在环氧树脂固化剂确定的情况下,砂胶比和砂子类型对环氧砂浆热膨胀系数影响较小,而选用不同固化剂对环氧砂浆热膨胀系数有很大的影响,可以通过选用性能优异的固化剂来降低环氧砂浆的热膨胀系数,尽量使环氧砂浆的热膨胀系数与被修补混凝土的相匹配。     

龚嘴水电站溢流堰面修补施工技术

鉴于龚嘴水电站运行发电已40多年,溢洪道溢流面未进行过修补,作为常规溢洪道7~9号溢流面冲蚀磨损严重,局部已可见钢筋,介绍了溢洪道溢流面采用NE-Ⅱ型环氧砂浆修补施工技术,包括材料选取、围堰结构和架立、环氧材料修补施工工艺等。     

环氧砂浆在水库裙板修复中的应用研究

采用环氧砂浆对水库裙板的混凝土进行修复,对环氧砂浆的分子结构、修补的作用机理、修补的工艺流程进行详细介绍,并评价其效果,可得出环氧砂浆修复工艺是目前性价比较高,易于实现的一种修复裙板的方法。     

H123水性环氧砂浆在水工混凝土结构修补中的应用

环氧砂浆作为一种混凝土结构修补加固材料,具有粘结强度高、干缩变形小、抗压模量低和抗侵蚀能力强的特点,在水利工程中得到广泛应用。通过H123水性环氧砂浆在白马湖穿运洞闸墩修补中的应用,分析闸墩病害产生的原因,介绍H123水性环氧砂浆的特性及在修补过程中的施工工艺。     

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.