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新浇大体积混凝土安全爆破振动控制标准 总被引:5,自引:0,他引:5
在清江隔河岩工程的现场,就爆破振动对新浇大体积混凝土的影响进行了试验研究。根据大量的产测资料提出了新浇大体积混凝土安全爆破质点振动速度新的控制值。按照这些控制值,在隔河岩工程的施工中对爆破振动进行了控制。 相似文献
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本文结合辽宁省清河水库溢洪道闸墩控制爆破拆除施工,从方案选择、爆破试验、爆破参数、爆破振动监测以及减震措施等方面论述了控制爆破施工技术,供混凝土拆除工程借鉴. 相似文献
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大坝溢流面受冻融破坏,表面裂缝、剥蚀、脱空是病险水库的常见现象。在大黑汀水库除险加固工程中,采取挖除20cm混凝土,新浇40cm厚混凝土的全断面补强方法,对溢流面进行修补处理。旧混凝土的开挖、新老混凝土接合面处理、裂缝防治等是薄层大面积溢流面混凝土修补设计和施工的关键技术问题。本工程采用微差控制爆破新技术、无机界面胶和聚丙烯纤维网新材料等,可供类似工程借鉴。 相似文献
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三峡临时船闸及升船机基础为前震旦花岗岩,岩体硬而脆,给开挖爆破造成困难,且施工中又要保护中隔墩岩体的整体稳定又要使新浇混凝土不受爆破震害。监理技术人员对控制爆破技术进行了深入的研究,制定开挖方案,确定爆破参数,审核爆破设计,检查重要部位的装药结构及起爆网络,完成了开挖任务。 相似文献
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本文介绍了四川南充东西关水电站闸坝工程1号泄洪闸下游齿槽新浇混凝土附近的石方沟槽控制爆破实例,可供爆破同仁参考。 相似文献
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通过采用浅孔控制爆破施工方法,对天花板水电站坝基揭露的f11、f15两个较大断层进行了拉槽开挖置换混凝土处理,现场采用严格的控制爆破施工工艺,有效地保护了已浇混凝土及坝基岩石的完整性,电站投产运行后,大坝运行安全稳定. 相似文献
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公伯峡电站厂房基础开挖与厂房砼浇筑平行施工中,在控制爆破方法、爆破规模、一次允许最大起爆药量的同时,对新浇砼面和基础岩石进行了爆破地震波质点振动速度监测,并对不同爆破条件下,新浇砼和基础岩石上的振动衰减规律作了测试.实测成果为工程质量控制提供了依据. 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