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281.
通过水力学模型试验着重分析了突扩比、跌坎深度和入池水流弗劳德数Fr0对消力池底板冲击区动水压力的影响。研究结果表明,在跌扩型底流消能工中,选择合适的突扩比、跌坎深度和入池水流弗劳德数Fr0,能有效降低消力池内底板和边墙的水力学指标。他们在一定的最优组合下,可既保证消力池中消能率高,又能满足消力池底板和边墙处动水冲击压力小的要求,避免造成底板板块的失稳破坏。 相似文献
282.
针对水库重力式大坝加高加固问题进行试验研究,对后帮式、前帮式、外包式以及戴帽式加高方式建立实验模型评价新旧混凝土结合面的粘结性能。抗折强度试验和微观电镜试验结果表明,四种类型的加高方式,外包式的结合面最大,抗折强度最高,粘结性能最强。采用水泥砂浆处理后增多了结合面的纤维状C-S-H凝胶,增强了新旧混凝土之间的粘结性能,合理的加固方式加上结合面处理有利于提高坝体的安全性能。 相似文献
283.
均匀湿颗粒材料边界滞回持水曲线的物理模型 总被引:2,自引:2,他引:0
非饱和土持水特性的滞回机理是土力学界的热点问题之一。将非饱和土看作“湿颗粒材料”并以“土-颗粒-系统”为视角更易认识其持水特性的滞回机理。以均匀湿颗粒材料为研究对象,用轴对称圆锥形孔隙内水分的充填和排出过程来模拟边界增、减湿过程,提出一种物理模型以描述其滞回特性的物理内涵,并利用已有文献中3种砂土和2种含黏砂土的持水试验结果验证了该模型在表征均匀湿颗粒材料边界滞回持水曲线时的有效性。该模型的优点在于不仅对同种均匀湿颗粒材料滞回的边界减、增湿持水曲线可采用同一组具有物理意义的参数模拟,而且可反映孔隙水内封闭气泡对持水曲线的影响。 相似文献
284.
山东省多措并举,建管并重,从组织领导、规模化发展、水质安全、基金筹集、管理体制、行业管理等方面入手,大力提升农村饮水安全水平。改变过去农村供水存在的"城乡分割、各自为战"的局面,大力发展规模化集中连片供水。走专业化管理的路子,主要推广自来水公司管理、供水企业管理、乡镇水利站管理三种管理模式。通过落实省政府规章的相关内容、加大检查督导力度、加强人员培训,强化行业管理,提高相关人员的从业水平和能力,为农村供水工程良性运行奠定管理和人才基础。 相似文献
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288.
根据阿海电站水轮机蜗壳现场安装中的关键工序和控制重点,整理、总结出大型机组蜗壳挂装、焊接、TOFD无损检测、施工进度及质量等方面的控制要求和施工经验。实际检测表明,已完成的4台水轮机蜗壳挂装和焊接质量全部达到优良标准。 相似文献
289.
Zhengmao Liu Xianguo Lu Sun Yonghe Chen Zhike Haitao Wu Yanbo Zhao 《Water Resources Management》2012,26(6):1455-1475
Naoli river basin(NRB), with an area of 24,863 km2, is the largest basin and also the largest marsh distribution area in Sanjiang Plain, Heilongjiang, China. The hydrological
evolution process of wetland in NRB has made a marked ecological responses for anthropic activities, also reflects the drying
trend of the Sanjiang Plain, Northeast China. Global climate warming also contributes to the hydrological evolution process.
The following key research results are obtained: (1) The monthly average water level of Naoli river at Caizuizi hydrological
station in different ages showed a marked decline tendency, the annual mean water level dropped from 96.63 m during 1960–1969
to 95.59 m during 2000–2005, the water level drawdown is 1.04 m; (2) The annual runoff flowing into wetlands in NRB decreased.
Duration of Naoli river and its tributaries being thoroughly frozen from riverbed to river-water-surface showed an prolonged
trend, and the water level drawdown in frozen seasons increased. The water storage capacities of wetlands in NRB declined.
(3) The interactions between ground water and surface water in wetland areas are close. The ground water level variation span
is bigger than that of surface water level in wetland areas of NRB. The drawdown of ground water level promotes the surface
water level to decline, correspondingly. In recent 20 years, the cultivated area extension of rice field in upstream NRB has
made an adverse influence on the hydrological processes of wetlands. (4) The wetland area decrease and farmland area increase
significantly contribute to the runoff depth decrease of wetlands in NRB. The runoff depth variability has been mostly posed
by anthropic activities. (5) Reservoirs, ditches and dykes in NRB have greatly changed the runoff generation processes. Thickness
of the seasonal frozen soil layer becoming thinner and the evaporation potential becoming bigger also contribute to the runoff
depth reduction and the water level drawdown of rivers. The present study results will provide a scientific basic for developing
an integrated watershed management program for NRB, especially, restoring the wetland hydrological processes, maintaining
or improving the wetland structure and enhancing the wetland service functions. 相似文献
290.
Due to sustained economic growth in China over the last three decades, urbanization has been on a rapidly expanding track. In recent years, regional industrial relocations were also accelerated across the country from the east coast to the west inland. These changes have led to a large-scale redesign of urban infrastructures, including the drainage system. To help the reconstructed infrastructures towards a better sustainability, a tool is required for assessing the efficiency and environmental performance of different renovation schemes. This paper developed an integrated dynamic modeling tool, which consisted of three models for describing the sewer, the wastewater treatment plant (WWTP) and the receiving water body respectively. Three auxiliary modules were also incorporated to conceptualize the model, calibrate the simulations, and analyze the results. The developed integrated modeling tool was applied to a case study in Shenzhen City, which is one of the most dynamic cities and facing considerable challenges for environmental degradation. The renovation scheme proposed to improve the environmental performance of Shenzhen City's urban drainage system was modeled and evaluated. The simulation results supplied some suggestions for the further improvement of the renovation scheme. 相似文献