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1.
为提高混凝土施工工作效率,节约施工成本,降低钢筋机械连接的施工难度,在云南糯扎渡水电站右岸导流洞洞身衬砌及进水塔混凝土工程钢筋施工中,采用了等强剥肋滚压直螺纹钢筋机械连接技术.介绍了这种技术在上述工程钢筋施工中的应用情况及其工艺流程、技术性能和经济分析. 相似文献
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钢筋机械连接技术及其在三峡工程中的应用 总被引:1,自引:0,他引:1
近年来,钢筋机械连接技术发展迅速,国内外均已开发出能充分发挥钢筋母材强度的等强级机械连接接头,施工速率快,成本低,从而为提高混凝土结构钢筋连接工程质量,加快工程进度,降低工程成本创造了条件。我公司将墩粗直螺纹技术和套筒冷挤压连接技术应用于三峡工程,提高了工效,降低了成本。 相似文献
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在水利水电建筑施工中,钢筋连接通常采用帮条焊接。为减轻工人劳动强度、降低施工成本、确保施工质量,我们在三期工程中研发并引进了钢筋机械连接技术。文章主要介绍了钢筋镦粗直螺纹连接技术和钢筋滚轧直螺纹连接技术在三峡工程三期厂坝、厂房钢筋机械连接的推广使用情况。 相似文献
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钢筋机械连接技术及其在三峡工程中的应用 总被引:2,自引:0,他引:2
近年来 ,钢筋机械连接技术发展迅速 ,国内外均已开发出能充分发挥钢筋母材强度的等强级机械连接接头 ,施工速度快 ,成本低 ,从而为提高混凝土结构钢筋连接工程质量 ,加快工程进度 ,降低工程成本创造了条件。我公司将墩粗直螺纹技术和套筒冷挤压连接技术应用于三峡工程 ,提高了工效 ,降低了成本。 相似文献
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钢筋机械连接技术具有连接质量好、速度快、操作简单、使用范围广、提高工效、节约成本等优点。文章介绍了钢筋机械连接技术在沙坡头水利枢纽工程上的应用情况。 相似文献
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钢筋等强镦粗直螺纹连接技术 总被引:1,自引:0,他引:1
为降低钢筋连接的施工难度,提高工作效率和节约施工成本,在公伯峡水电站工程厂房坝段的钢筋施工中,采用了镦粗直螺纹套筒连接的新技术,提高了现场工作效率,降低了施工人员的劳动强度,并积累了丰富的经验。 相似文献
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介绍乌江彭水水电站引水发电系统应用粗直径钢筋直螺纹机械连接技术。在乌江彭水水电站引水发电系统工程混凝土施工中,采用粗直径钢筋直螺纹机械连接技术替代传统的钢筋制安技术,降低了混凝土施工中钢筋制安的施工难度和劳动强度,提高了工作效率和工程质量,节省了工程投资和建设工期,保证了彭水水电站防洪度汛及发电目标的实现。 相似文献
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钢筋等强度剥肋滚轧直螺纹机械连接技术是对钢筋先行剥肋.后滚轧出直螺纹,再与配套的直螺纹套筒进行连接。在公伯峡水电站堆石面板坝混凝土面板的钢筋制安中.采用该技术替代传统的面板钢筋制安技术.降低了混凝土面板钢筋制安的施工难度和劳动强度.提高了工作效率和工程质量.更提高了公伯峡水电站工程的科技含量。 相似文献
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钢筋直螺纹接头技术属于机械连接技术的一种,它不同于传统的焊接技术的等强级机械连接技术。它具有加工安装速度快,安装操作简便,成本低的特点。该项技术在三峡工程中的成功引进并使用,为加快三峡二期工程的施工进度和降低工程成本起到了非常重要的作用。钢筋直螺纹连结技术在其它水电工程中有着很好的推广使用价值。 相似文献
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建筑施工技术是一门综合性的应用技术。南昌生米大桥施工中采用了一些国内先进的新技术、新工艺和新材料:如自平衡测试技术、钢筋机械连接技术、低松弛高强钢绞线的应用与连接技术、塑料波纹管与真空辅助灌浆技术、冷扎带肋钢筋焊网应用技术、移动模架施工技术等,成功地解决了施工中的各项难题,取得了很好的效果。 相似文献
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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。 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
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.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
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. 相似文献