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郑文超 《水科学与工程技术》2016,(4):60-63
阐述了传统配筋技术的缺点和不足,三维配筋的发展及独特优势,介绍了配筋软件的功能及在水利行业中的应用,在节省时间成本、劳动力成本上的优越性,提出了软件的一些不足和建议,并总结了软件在水利行业应用的必要性。 相似文献
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西藏果多水电站进水口顶部因结构特点及门机布置、运行需求,需在两侧端部向上游各悬挑7.35 m的大型牛腿。对于该类型大体积牛腿,按照现行规范进行结构配筋计算,计算所得配筋很小,不满足最小配筋率;但若按最小配筋率选筋,则往往配筋量较大、布置密集,影响混凝土的浇筑施工和振捣密实,而西藏高寒地区对于混凝土施工质量控制要求严格。结合果多水电站工程,采用多种方法对大体积混凝土进行配筋计算,并运用有限元法进行配筋验算和结构论证,得到较为合理、经济的配筋结果。在满足结构功能需求的前提下,建议尽可能减小牛腿结构尺寸,另外在设计过程应尽可能避免该类型大体积悬挑结构的出现。 相似文献
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水工大体积结构配筋计算中应用最小配筋率的规定,明显地存在着不合理现象,为此,本文推荐按“临界截面”的新概念进行计算,并列举了其他四种方法的结果,以资对比. 相似文献
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ReStation三维配筋系统在导流隧洞工程中的应用 总被引:1,自引:0,他引:1
受水力学条件、结构稳定要求等因素影响,导流隧洞进水口结构型式一般较为复杂,结构配筋存在较大难度。以杨房沟水电站导流隧洞工程为例,通过ANSYS有限元计算确定结构配筋参数,再输入至Re Station三维配筋设计系统,通过智能钢筋抽图准确绘制施工图纸,有效地解决了复杂进水口结构大体积混凝土的配筋问题,可为其他类似工程提供借鉴。 相似文献
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对于结构复杂的水工大体积混凝土,无法按杆件结构力学法求得截面内力来配筋;而采用有限元法分析时,直接模拟钢筋不具可操作性。将有限元法的应力积分得到的内力结果应用到非杆系钢筋混凝土的配筋计算公式中,进而可求出配筋量。以观音岩水电站导流底孔坝段及进水塔结构为例,其整体模型结构复杂、体型较大、设计水头较高,采用ANSYS软件建立三维有限元模型,并利用应力计算结果进行了高应力区的配筋计算。计算过程清晰、结果可信度高,供类似工程的设计人员参考和探讨。 相似文献
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水资源安全问题一直是研究热点,基于生产-消费状况揭示区域虚拟水流动,对了解水资源利用状况和水资源可持续利用具有重要意义。基于虚拟水视角,以灌溉用水和绿水核算区域农业虚拟水生产,以居民膳食消费核算居民虚拟水消费,以两者的差值核算并分析了京津冀地区在生产-消费模式下农业虚拟水流动特征及对区域水资源压力的影响。结果表明:(1)2004-2015年间,河北、天津、北京年均作物生产虚拟水分别为353.1亿m3、22.9亿m3和16.0亿m3,年均畜牧产品生产虚拟水分别为445.3亿m3、47.6亿m3、36.7亿m3;河北、天津作物虚拟水呈现下降趋势但变化趋势不明显,北京作物生产虚拟水呈现出持续性的下降趋势;河北、天津畜牧产品虚拟水均呈现出先增加后减少最后趋于缓慢上升态势,北京畜牧产品虚拟水呈现持续下降趋势。(2)2004-2015年河北、天津和北京年均虚拟水消费分别为243.7亿m3、61.6亿m3和98.3亿m3,虚拟水消费均呈现出上升趋势。(3)河北省为虚拟水输出型,输出量呈明显的下降趋势,北京市和天津市为虚拟水输入型,输入量呈增加趋势。(4)2004-2015年年均水资源压力指数呈现河北天津北京,水资源匮乏度呈现为天津北京河北,水资源自给率呈现河北天津北京,北京和天津对外部虚拟水输入的依赖程度逐渐增加。京津冀水资源面临着严重的短缺问题,水资源超载严重。提高农业用水效率,优化种植结构,引导合理的膳食结构调整,从生产和消费两方面同时入手是解决京津冀水资源问题的关键措施。 相似文献
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Machiwal Deepesh Jha Madan K. Singh P. K. Mahnot S. C. Gupta A. 《Water Resources Management》2004,18(3):219-235
Water-harvesting structures have the potential to increase the productivity of arable lands by enhancing crop yields and by reducingthe risk of crop failure in arid and semi-arid regions, where water shortages are common because of scanty rainfall and its uneven distribution. In semi-arid regions of Rajasthan, India, existing practice of harvesting rainwater is through anicut and earthen embankments. Because of higher costs and higher technical skills involved in the construction of these structures, these structures have not been accepted by the resource-poor local people. Therefore, in the present paper, the detailed design of some low-cost water-harvesting structures using locally available materials and adaptable to the socio-economic conditions of the beneficiaries is discussed. Two types of cost-effective water-harvesting structures, which include dry stone masonry and upstream-wall cement masonry of heights 1, 2, and 2.5 m for catchments of less than 10, 10 to 20, and 20 to 30 ha, respectively are proposed and designed. The analysis of costs involved in constructing dry stone masonry and upstream-wall cement masonry water-harvesting structures, emergency spillway, anicuts and earthen embankments revealed that the earthen embankments have the least cost of construction whereas the anicuts have the highest construction costs for all the selected heights. However, based on the past experiences, earthen embankments are not suitable for the semi-arid regions of Rajasthan. The economic evaluation of the proposed structures indicated that the dry stone masonry structures are very cost-effective for the region with a benefit-cost ratio of 3.5:1 and the net present worth value of Rs. 102978. Although the economic indicators ranked the upstream-wall cement masonry structures lower than the dry stone masonry structures, the former has greater stability and strength compared to the latter. In practice, both the cost-effective water-harvesting structures (i.e., dry stone masonry and upstream-wall cement masonry) are gaining wide acceptance and popularity in the region through some nongovernmental organizations, which have adopted the design presented in this paper. 相似文献
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本文用确定性切变模拟时均流动的作用,用大尺度随机应变反映大尺度相干结构中无旋部分的作用,对时均流动与大尺度相干结构夺小尺度结构的作用进行了探讨,并分析了在应变率与切变率较小的情况下小尺度结构的湍能及雷诺应力的变化趋势。 相似文献
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This article reviews scouring and liquefaction issues for anchor foundations of floating offshore wind farms. The review is organized in two sections: (1) the scouring issues for drag-embedment anchors (DEAs) and other subsea structures associated with DEAs such as tensioners, clump weights, and chains in floating offshore wind farms; and (2) the liquefaction issues for the same types of structures, particularly for DEAs. The scouring processes are described in detail, and the formulae and design guidelines for engineering predictions are included for quantities like scour depth, time scale, and sinking due to general shear failure of the bed soil caused by scour. The latter is furnished with numerical examples. Likewise, in the second section, the liquefaction processes are described with special reference to residual liquefaction where pore-water pressure builds up in undrained soils (such as fine sand and silt) under waves, leading to liquefaction of the bed soil and precipitating failure of DEAs and their associated subsea structures. An integrated mathematical model to deal with liquefaction around and the resulted sinking failure of DEAs, introduced in a recent study, has been revisited. Implementation of the model is illustrated with a numerical example. It is believed that the present review and the existing literatures from the “neighboring” fields form a complementary source of information on scour and liquefaction around foundations of floating offshore wind farms. 相似文献
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水工建筑物的病害治理需要有可靠的技术,其中修补材料的选择是十分重要的一环。本文中在总结中国水利水电科学研究院结构材料研究所参与的修补工程及使用的材料的基础上,介绍了近年来有关国内外及该所新研制、开发应用的修补材料及其技术、工程应用等经验,可供科研、设计、施工参考。 相似文献
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丹江口大坝加高初期工程裂缝处理施工工艺 总被引:2,自引:2,他引:0
姜俊峰 《南水北调与水利科技(中英文)》2009,7(2)
丹江口大坝加高工程的施工是按照结构设计进行的,而丹江口大坝老坝体的使用标准是由裂缝来控制的.因此丹江大坝初期工程的裂缝处理工作是整个大坝加高工程的重中之重.主要阐述了丹江大坝初期工程裂缝的成因及处理的施工工艺. 相似文献
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病险水工建筑物可靠性评估方法初探 总被引:4,自引:0,他引:4
水工建筑物可靠性评估是水利工程管理中急需解决的问题,将水工建筑物分解为由分部工程组成的层次结构,引入子系统概率重要性系数,用层次分析法导出水工建筑物系统可靠度指标的实用计算方法。 相似文献
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湍流边界层外区的相干结构主要表现为大尺度横向涡。本文针对横向涡的特性,提出了横向涡的概化模式。而后对横向涡中单个异质悬浮粒子的运动进行了数字模拟,对粒子的尺度与密度,横向涡特性及小尺度运动对悬浮粒子运动的影响进行了探讨。 相似文献
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