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结合工程实例阐明了利用灰色关联分析确定影响大坝运行期安全主要因子的方法,并对不同样本进行关联度计算,证明灰色关联分析中,真正唯一反映因子之间关联度大小的是关联度的排列顺序,即关联序,该方法可在大坝观测数据处理中应用。 相似文献
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基于MA理论并结合水库生态系统优化了指标体系,通过功能价值法估算了南水北调中线17个水库/湖泊2008—2019年库区生态系统服务价值,运用灰色关联分析计算了各指标对总价值的关联度,分析了南水北调中线工程对沿线生态系统的影响,为南水北调中线工程水资源管理及水生态保护提供了依据。 相似文献
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针对龙滩工程对各环境因子复杂的影响需进行综合分析评价,以便了解工程兴建前后的环境总体情况,以及工程的可行性,并为选择工程方案提供科学依据。采用多级模糊综合评价法及灰色关联分析综合评价法对龙滩水电工程环境影响进行了分析后,认为工程兴建是可行的。 相似文献
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根据灰色关联分析原理,从多维空间概念出发,将距离平方和最小扩展为广义加权距离最小,通过求条件极值建立了地下工程围岩稳定分级的灰色关联优化模型,并应用于工程实例中。计算结果表明,地下围岩稳定分级的灰色关联优化模型正确可靠,具有一定的实际使用价值。 相似文献
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通过对参与浙江省水利建设工程投标人的问卷调查得样本数据分析,引入灰色关联分析的方法,建立评价模型,揭示影响投标人中标率的各因素的关联影响程度。针对各影响因素的作用程度,对降低招标投标的社会成本提出了建议。 相似文献
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在水利水电工程施工期间混凝土施工是非常重要的环节之一,且对水利水电工程也有非常密切的关联。本文对水利水电工程中混凝土施工管理的意义和必要性进行分析和探讨,分析混凝土施工管理过程中技术要点并提出强化措施。一、 相似文献
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预算、施工、内业是水利工程项目建设中3个重要环节,三者之间相互关联、相互影响、相互制约。从水利工程预算、施工、内业3个环节之间的相互关联入手进行分析探讨,总结出如何在工程项目建设中做到三者的统一协调,进而优化管理提高工程效益。 相似文献
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虽然由于其所处区域的特殊性,怒江水电移民人数少,但影响层面却相对复杂多样。通过对怒江水电移民与区域发展的相关层面分析,发现怒江水电移民与生态、人口、土地、文化等方面存在不同属性的关联,其中人口有直接的关联,而土地既与水电移民产生直接关联,同时也是其他关联发生的重要媒介。在这些关联因素中,水电移民与生态的关联最为复杂,也最为重要,而水电移民与文化的关联则更强地体现出二者的互动关系,水电移民与文化的相互关联性使水电移民工程体现出更强的社会性。 相似文献
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模糊灰色理论在围岩类别评定中的应用 总被引:2,自引:0,他引:2
根据灰色系统理论有关灰关联分析之观点及其新的理论模型,结合模糊集理论有关方法思路,引用一种模糊灰关联模式识别方法,将其应用于硐室开挖围岩类别的评定,有效服务于隧洞工程施工技术方案的决策及管理,在水布垭电站工程中得到实际应用。 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