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大伙房水库输水工程合同实施阶段的工程变更管理,主要是在控制工程项目变更的同时,对变更工程项目的增减、工程量的变化、变更工程价款的确定及工程计量与支付等工作实施的管理与控制.依据合同条款.严格控制工程项目变更,准确确定工程项目的增减;对变更工程量进行认真准确的计算;确定变更工程的价款,及时准确地对变更工程进行计量及价款支付;从而达到对工程变更的科学管理和有效控制. 相似文献
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要真正做好工程造价管理工作,建设单位必须高度重视工程变更管理,严格执行变更工作程序,及时有效控制工程变更价款。 相似文献
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工程投资控制的主要任务是工程计量、工程进度款的审核、索赔处理、价差调整等。工程计量要求监理工程师掌握正确的计量方法,以保证计量的准确。计量的基本原则是按图纸计量,在监理实施细则中要规定好计量程序,在土石方开挖完成后,监理工程师应及时到现场进行土石鉴定,准确计算出土石的方量。在工程进度款结算过程中,产生问题和分歧较多的有结算、审核时间、超前支付,拖后支付,要妥善处理。工程索赔问题产生的原因主要有工期 相似文献
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在工程施工阶段,商务工程师的主要任务是做好工程的计量支付、新增工程和索赔的管理与控制。工程的计量支付要与工程进度和质量相结合,防止超前支付和对质量不合格的工程量的支付。包含在合同变更范畴以内的新增工程,其单价的确定应以合同为基础。在施工阶段出现的每一项施工索赔事项,都应按照工程项目合同条款的具体规定协商解决。为了保证工程进度计划的顺利实施,监理单位协助业主推行了“目标责任制”。在月付款滞后于施工进 相似文献
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关于工程变更和索赔问题的讨论 总被引:5,自引:0,他引:5
目前在土水工程管理中,往往对工程变更款也采取施工索赔的方式来解决,这无疑增加了索赔的难度。通过对工程变更与施工索赔的定义、处理程序、付款方式等区别的分析,提出承包商应合理利用工程变更条款,将施工过程中出现的图纸与技术规范中的缺陷、业主要求的修改、工程师的不适当拒绝与苛刻检查等列入工程变更,设法使工程变更合法化。并举实例说明了其效果,使承包商获得利益,减小损失。 相似文献
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加强工程施工合同管理是控制工程造价的重要手段 ,要从工程招投标中合同价款的确定、工程实施过程中变更和索赔的处理等方面加强管理 ,合理有效地控制工程造价 相似文献
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《给水排水》2014,(9)
正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc. 相似文献
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The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L?1, the median total phosphorus was 0.29 mg L?1 and the median total nitrogen was 1.56 mg L?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd. 相似文献
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Carbon dioxide (CO2) and methane (CH4) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO2 and CH4 diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 106 t CO2eq km2 per year, or 24 × 106 t CO2eq per year. This corresponds to a plant emission factor of 3.18 kg CO2eq MWh?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO2eq per year, or 5.83 kg CO2eq MWh?1, which is in the lower range of the studied reservoirs. 相似文献
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解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明:库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。 相似文献
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Mutlu Ozdogan Curtis E. Woodcock Guido D. Salvucci Hüseyin Demir 《Water Resources Management》2006,20(3):467-488
Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary
data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated
fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding
of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold
(from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area
from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate
a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a
volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes
in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future
water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation
due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation
conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation
sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead
to improved management, and by extension, sustainability of water resources in the region. 相似文献
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River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35–90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m?2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m?2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60–80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept. 相似文献
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Peter M. Gibbs 《国际水》2013,38(4):547-557
Abstract A professional Land Surveyor (Geomatician) describes the Hydrogeologists' survey requirements of a major water resources assessment for the government of The Sultanate of Oman (1992 to 1996). The need for objective specifications is stated. Specialist terms like geoid, spheroid, Mean Sea Level are explained and how to relate spheroidal levels to the geoid. Methods like traditional survey, satellite survey, and photogrammetry are introduced. The paper encourages coordinated working for the benefit of water resource assessment and recommends employment of the professional land surveyor for major studies. 相似文献
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Reports concerning the influence of dams on river hydrology vary among researchers, interest groups and government agencies. These often contradicting statements may occur because changes in hydrology caused by dams are distinct for each dam and river watershed. The objective of this research was to use site specific techniques to determine if the 1967 installation of the Carlyle Dam, lower Kaskaskia River, Illinois, altered flood frequency and duration within the forested floodplain located below the dam. Results indicated a decrease in flood duration and frequency, and a decrease in annual flood frequency variation at a site 6.4 km below the dam. Pre‐dam versus post‐dam differences in flood frequency and duration at the site 32.2 km below the dam were related to climate rather than dam effects. Although dam impacts are a concern, this research shows that distance downstream from the dam and downstream tributary and watershed characteristics should be considered before assuming that the dam has changed hydrologic parameters for portions of rivers. This research also indicates that areas of the lower Kaskaskia River may still maintain hydrologic ecological integrity, and could be targeted for restoration and adaptive management purposes. Hydrologic modelling combined with river gage and on‐site well measurement techniques presented in this study could provide detailed flood frequency and duration information for land use, sociological and geomorphological questions in focus areas within river floodplains. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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用Vray三维渲染引擎来渲染三维场景,其质量和速度是由一些影响因素和参数设置决定的,不同的参数和因素,可以得出不同的三维渲染效果.因此,分析、优化三维渲染质量和速度的影响因素,正确、合理的选择参数对提高Vray最后渲染阶段的质量和速度非常重要. 相似文献
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本文从两相流体动力学的守恒方程出发,考虑固相、液相的相对运动,推导了可以考虑场的不均匀性和流体压缩性的统一形式的控制方程,并对方程所基于的物理概念和相互联系进行了必要的分析。通过对方程适当形式的表达,可导出用于大、小变形固结、渗流和沉积的简化方程,显示了在不同领域的三个理论存在一定的统一性。方程推导过程并未对本构关系加以限制,适用范围较广。依据实际问题的要求,作了不同形式的简化。 相似文献