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对于水利工程项目业主来说,招标阶段是项目风险识别、评估和预警的关键时期。对水利工程项目招标阶段的潜在风险进行理论分析,建立了相应的风险辐射图模型。以浙江省某围涂工程为例,利用风险辐射图模型对其招标阶段的风险因素作出定量评估,从而建立有针对性的风险预警机制,达到有效防控项目风险的目的,推进该工程项目的招标工作和项目实施。 相似文献
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合理的风险分配是水利工程BOT项目成功的重要保证。运营期是水利工程BOT项目全寿命周期中的重要阶段,因此如何对运营期内的风险进行识别并合理分配已成为亟待解决的问题。文章通过分析水利工程BOT项目的特点,识别出了运行期内对项目经济效益影响较大的政治/法律风险、运营风险、经济风险、收益风险和其他风险5类风险,同时给出了相应的风险分配方法,为水利工程BOT项目运营期风险分配提供参考。 相似文献
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余勇泰 《河南水利与南水北调》2018,(9)
高效的合同管理,对提高水利工程整体规范程度有很大作用,提高合同管理是水利工程建设有序进行的重要保证。复杂的外部环境使得项目面临多样的风险。文章以水利工程项目为例,探讨水利工程项目从招投标到工程竣工的运营过程中如何加强合同管理以降低项目运营风险的问题,为后期项目合同管理提供有效参考和依据。 相似文献
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水利工程项目评价具有自身的特点,结合项目绩效理论,从项目绩效评价的基本内涵出发,对水利工程绩效评价工作进行一些思考,对如何从水利工程的项目核心价值中进行水利工程绩效评价进行了探讨和分析。 相似文献
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水利工程项目评价具有自身的特点,结合项目绩效理论,从项目绩效评价的基本内涵出发,对水利工程绩效评价工作进行一些思考,对如何从水利工程的项目核心价值中进行水利工程绩效评价进行了探讨和分析. 相似文献
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高春锦 《河南水利与南水北调》2016,(6):42-43
水利工程具有投资大、建设周期长、涉及方面广以及建设过程中不确定因素多等特点,承包商在项目建设过程中会面临众多风险。针对水电工程建设项目影响投标报价风险因素较多的特点,文章分析了纵向视角下项目选择阶段的业主合作诚信度风险、项目资金供应风险、交易公平风险和投标决策阶段风险,详细列举了横向视角下的政治风险、经济风险、自然环境风险、社会环境风险、合同风险、工程变更风险、技术风险和其他风险,通过对水电工程项目投标报价风险进行分析,为承包商投标报价提供决策依据。 相似文献
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业主方的项目管理是水利工程建设项目管理的核心.文中重点探讨了水利工程业主方在整个项目周期各阶段的管理目标和管理内容,以及水利工程业主方项目管理存在的问题及对策. 相似文献
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为实现政府监管部门对水利工程建设质量事中事后的有效监管,首先,在梳理国内外水利工程质量风险评价相关研究、部分省份水利工程建设质量监督检查意见的基础上,分别归纳整理出水利工程在开工前、建设实施两个阶段的初始质量风险评价指标体系,并采用探索性因子分析方法对指标体系进行精简;其次,采用多层次灰色评估法和基于信息集结算子的AHP法构建水利工程质量风险评价模型,对水利工程开工前、建设实施两个阶段的风险进行评价,识别出重点监管项目和部位,提升政府水利工程监管的效率;最后,选取典型水利工程建设的项目案例进行分析。案例分析证明:本文构建的两阶段质量风险评价体系及方法具有合理性,可为质监部门明确水利项目监督管理重点提供相关建议。 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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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
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We tested the recolonization of the phytobenthic community in the tailwaters of Glen Canyon Dam following long- and short-term experimentally induced desiccation. The response of Cladophora glomerata, Oscillatoria spp., miscellaneous phytobenthos species and periphyton was studied over 18 weeks using three treatments: (1) undisturbed control cobbles from the submerged zone; (2) cobbles desiccated and replaced into the submerged zone; and (3) cobbles desiccated and replaced into the varial zone. Periphyton density and compositional response resulting from these treatments were also examined. Desiccation treatments were significantly different in biomass from controls throughout the study. The biomass of desiccated and replaced river cobbles averaged <30% of the controls for C. glomerata and periphyton during the 18-week recolonization period. In contrast, the biomass of the control Oscillatoria and miscellaneous phytobenthos species averaged only 3 and 50% of that in the desiccation treatments, respectively. Cladophora, the dominant alga, comprised 77% of the phytobenthic biomass. A significant positive relationship between discharge, Cladophora and periphyton biomass was present in all treatments, while there was a negative relationship with discharge for Oscillatoria and miscellaneous phytobenthos species. There was a significant inverse correlation, as well as a pattern of separate biomass dominance, between C. glomerata and Oscillatoria. Cladophora was the dominant phytobenthos species on cobbles below the baseflow and Oscillatoria was dominant on cobbles in the varial zone. In general, the Cladophora biomass decreased under intermittent drying conditions, while Oscillatoria declined under permanently wet conditions. Diatom composition was not significantly different between treatments; however, their density was lower on desiccated cobbles. Diatom density on desiccated cobbles in the submerged and varial zones averaged 69 and 42% of that of the controls, respectively. Recovery and maintenance of benthic resources are hindered by fluctuating flow regimes driven by electricity and irrigation requirements. Repeated desiccation of the phytobenthos has major effects on the bottom-up interactions in the Colorado River ecosystem. © 1998 John Wiley & Sons, Ltd. 相似文献