检索结果-南通市图书馆

THE BACKWATER HEIGHT DUE TO OBSTRUCTION BY PIERS OR PILES

在线全文

学校读者我要写书评

暂无评论

THE BACKWATER HEIGHT DUE TO OBSTRUCTION BY PIERS OR PILES

草被覆盖下坡沟系统坡面流能量变化特征试验研究

第九次河流泥沙国际学术大会

作者： Guobin LINanjing hydraulic research {2. Nanjing 2.002. china. Ruinian PU Jiangsu hydraulic Survey and Design {2. Yangzhou 2.5009 chinaHongjun REN yellow River’s Wanjiazhai Hydro Project Power Station Management Bureau Shanxi 036412.chinaWeijun ZHOU Jiangsu hydraulic Survey and Design {2. Yangzhou 2.5009 china

＜正＞This paper presents research results on the backwater height due to obstruction of piers or piles. By using the momentum equation and taking into account the resistance caused by piers, an equation to calculate the backwater height was derived and compared with others. The research results indicate that the backwater increases with Froude number and resistance of piers. With regards to the normal subcritical flow, effect of Froude number can be ignored. The resistance to the flow caused by piers is affected by many factors such as shape of piers, longitudinal and transversal arrangements, depth of submergence, relative water depth, incident angles of oblique flows, number of longitudinal and transversal piers, and flow velocity, etc. Results from this equation are in general agreement with those obtained using those derived by other authors for the calculation of the backwater height under the same condition. However, the present equation takes various factors into account and can be employed in many situations.

关键词： Pier Backwater height Froude number Friction Local head loss

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

水土保持学报 2005年第5期19卷 13-17页

作者：李勉姚文艺陈江南丁文峰杨剑锋李莉杨春霞黄河水利科学研究院水利部黄河泥沙重点实验室河南郑州450003 长江科学院湖北武汉430010

坡面侵蚀是水流能量作用的结果,草本植被对坡面流能量的作用有重要影响,研究坡沟系统坡面草被不同盖度及空间配置下坡面流能量的变化过程与特征,对于揭示草被减蚀作用机理有重要意义。本文利用实验土槽和放水冲刷试验方法,研究了2.流量... 详细信息

坡面侵蚀是水流能量作用的结果,草本植被对坡面流能量的作用有重要影响,研究坡沟系统坡面草被不同盖度及空间配置下坡面流能量的变化过程与特征,对于揭示草被减蚀作用机理有重要意义。本文利用实验土槽和放水冲刷试验方法,研究了2.流量(3.2.L/min和5.2.L/min),坡面5种草被盖度(0,30%,50%,70%和90%)及3种空间配置(坡上部、坡中部、坡下部)下,坡沟系统坡面径流能量的变化过程与特征。结果表明,有草断面比无草断面下的径流动能、势能普遍偏小,变化幅度也较平缓;各断面能耗时间上呈下降-稳定的变化趋势,空间上随着径流流程的增加呈显著增加趋势;坡面流能耗变化过程与径流含沙量变化过程基本一致,裸坡情况下二者关系更为密切。

关键词：坡沟系统坡面流径流能量径流能耗草被覆盖

在线全文

学校读者我要写书评

暂无评论

预应力施工阶段混凝土压力管道受力性能研究

水力发电学报 2004年第1期23卷 36-41页

作者：赵顺波李晓克赵国藩华北水利水电学院土木工程系郑州450011 大连理工大学土木水利学院大连116023

本文基于环形预应力作用机理和弹性双层圆筒计算模型 ,推导出压力管道在预应力作用下的应力和径向变形解析计算公式 ,与模型试验和三维有限元仿真计算结果进行了对比分析 ,表明所提出的理论计算公式可用于混凝土压力管道在预应力施工阶... 详细信息

本文基于环形预应力作用机理和弹性双层圆筒计算模型 ,推导出压力管道在预应力作用下的应力和径向变形解析计算公式 ,与模型试验和三维有限元仿真计算结果进行了对比分析 ,表明所提出的理论计算公式可用于混凝土压力管道在预应力施工阶段的应力和变形控制设计。

关键词：水工结构工程应力与变形模型试验有限元分析压力管道预应力混凝土

水利工程施工期业主风险的多层次模糊综合评价研究

在线全文

学校读者我要写书评

暂无评论

水力发电学报 2008年第4期27卷 141-145页

作者：田林钢宋永嘉孙淑侠华北水利水电学院郑州450008 陕西省水环境工程勘测设计研究院西安710021

水利工程施工期的业主风险是影响工程质量和进度的重要因素。为保证新疆某水库引水西延干渠工程的顺利施工,对业主风险进行科学管理是非常必要的。研究过程中采用专家调查法分析得到工程施工期业主的风险因素清单,并建立多层次模糊综合... 详细信息

水利工程施工期的业主风险是影响工程质量和进度的重要因素。为保证新疆某水库引水西延干渠工程的顺利施工,对业主风险进行科学管理是非常必要的。研究过程中采用专家调查法分析得到工程施工期业主的风险因素清单,并建立多层次模糊综合评价体系进行评估论证,后以评价结果为依据,制定了科学的风险管理方案,采取多种措施进行风险控制和防范,保证了西延干渠工程施工建设的顺利进行。

关键词：水利工程业主风险层次分析法风险分析多层次模糊综合评价

区域水资源短缺风险的SPA—VFS评价模型

在线全文

学校读者我要写书评

暂无评论

水电能源科学 2009年第4期27卷 31-33,225页

作者：王富强韩宇平汪党献赵若华北水利水电学院水利学院河南郑州450011 中国水利水电科学研究院北京100044

基于集对分析原理,选取区域水资源短缺风险程度的风险率、脆弱性、可恢复性、重现期和风险度为评价指标,建立了基于集对分析—可变模糊集的区域水资源短缺风险评价模型。湖北漳河灌区实例结果表明,灌区水资源短缺风险均处于较低风险水平... 详细信息

基于集对分析原理,选取区域水资源短缺风险程度的风险率、脆弱性、可恢复性、重现期和风险度为评价指标,建立了基于集对分析—可变模糊集的区域水资源短缺风险评价模型。湖北漳河灌区实例结果表明,灌区水资源短缺风险均处于较低风险水平,预测结果与灌区现状的开发利用程度、缺水量相符,该模型具有一定的可操作性和实用性,并为区域水资源规划和管理提供决策依据。

关键词：集对分析可变模糊集 SPA—VFS评价模型水资源短缺风险分析

玉米黄粉胡萝卜素的提取及其脂溶制剂稳定性研究

在线全文

学校读者我要写书评

暂无评论

食品科技 2003年第8期28卷 95-97页

作者：沈国鹏杜斌韩志慧郑州大学化工学院郑州450002 郑州大学药学院郑州450052

研究了以玉米淀粉厂副产品玉米黄粉为原料,提取类胡萝卜素的最佳工艺条件。用复合萃取剂一次提取率达96.5%,脂溶性产品在445nm最大吸光度%11cmE≥0.58,并对其保存稳定性进行了研究。

关键词：玉米黄粉胡萝卜素稳定性萃取

SOFT CLAYS ALONG THE COAST OF china

在线全文

学校读者我要写书评

暂无评论

china Ocean Engineering 1987年第4期 47-62页

作者： Wei Rulong Senior Engineer, Nanjing hydraulic research {2., Nanjing

- At the sites of the harbours along the coast of china, especially in the vicinity of the mouth of the yellow River, the Yangtze River and the Pearl River, the soil strata often consist of recently deposited alluvial sediment. Therefore, under the foundations of harbour engineering structures there are always soft clays of considerable thickness. In this paper, the definition of soft clay is at first given according to the Chinese Foundation Code of Harbour Engineering. Then the physical and mechanical properties of some soft clays at the sites of harbour along the coast of china are summarized. These soft clays are classified into four types according to their physico-mechanical characteristics: very soft clay (mud), soft (muddy) clay, soft (muddy) silty clay and very soft clay (mud) mixed with lumps of sand. It is seen from the collected data that the physico-mechanical characteristics for soft clay of the same type at various sites along the coast of china are very similar, which implies that these soft clays may be formed from the similar geological origin and in similar environmental condition. It is well known that the soft clay with such unfavourable engineering properties as high water content, low shear strength, high compressibility and low permeability, is a rather weak foundation for structures, hence there would be frequently some problems happened during the construction of structure on it. However, these problems more or less can be avoided, provided that the soft clay strata have been explored, tested and analyzed carefully and appropriate measures are taken during construction. The problems usually encountered in the construction on soft clay are deformation and stability. The experiences and lessons learned on these respects in china are illustrated with 10 case histories of different types.

关键词： SOFT CLAYS ALONG THE COAST OF china

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

南水北调西线一期工程滑坡崩塌体稳定性评价

山地学报 2005年第5期23卷 69-74页

作者：黄志全刘希林华北水利水电学院岩土工程系中国科学院水利部成都山地灾害与环境研究所郑州450008 成都610041

南水北调西线工程的主要目标是解决西北、华北地区缺水问题。在现有资料和工作深度的基础上,对工程区滑坡崩塌体的稳定性进行了评价研究。研究表明:在整个工程区,库区内崩塌最为发育,滑坡较少;在不同的库区,岸坡的变形呈现出空间不均匀... 详细信息

南水北调西线工程的主要目标是解决西北、华北地区缺水问题。在现有资料和工作深度的基础上,对工程区滑坡崩塌体的稳定性进行了评价研究。研究表明:在整个工程区,库区内崩塌最为发育,滑坡较少;在不同的库区,岸坡的变形呈现出空间不均匀性。崩塌堆积体主要发生在碎裂(松散)岩质岸坡地段,分布于库区的崩塌堆积体中,稳定和基本稳定的占崩塌堆积体总数的2.%,潜在不稳定的占崩塌堆积体总数的50%;分布于库区的滑坡堆积体中,潜在不稳定或不稳定的滑坡数量较多。

关键词：南水北调滑坡崩塌体稳定性评价

ANALYSIS ON THE VARIATION OF SEDIMENT YIELD IN SANCHUANHE RIVER BASIN IN 1980s

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment research 1992年第3期 1-20页

作者： ZHAO Wenlin Senior Engineer, institute of hydraulic {2., yellow River Conservancy Commission JIAO Enze Senior Engineer, institute of hydraulic {2., yellow River Conservancy Commission WANG Guangren Senior Engineer, Soil and Water Conservation Bureau, Shanxi Provincial Water Resources Department MENG Xiaoren Engineer, Soil and Water Conservation Bureau, Shanxi Provincial Water Resources Department

Making use of empirical relationships of precipitation-runoff and runoff-sediment load, as well as statistic method associated to soil conservation measures, the variation of sediment yield in Sanchuanhe River Basin is studied. The results show that the mean annual sediment yield in this basin in 1980s is 9.63 ×106t with a decrease of 2.. 18 × 106 t compared with the sediment yield in the period from 1957 to 1969. The variation of rainfall and the intensified human activities, including the soil conservation measures and water conservancy works, are responsible to this decrease. Due to variation of rainfall, the mean annual sediment yield is reduced by 11.95 - 14. 15 ×106 t in 1980s as estimated by the hydrological method. The reduction due to human activities is 13. 11- 14.82.×106 tons and 11.64 ×106 tons estimated respectively by the hydrological method and by the statistic method of soil conservation. The contribution of these two aspects to the total decrease is more or less 50% respectively. Among the reduction in sediment yield due to human activities, the soil conservation measures contributes the major part, being 88.2. to the total. The check-dams play the most important role, being 75.4%, to the decrease due to the soil conservation measures.

关键词： ANALYSIS ON THE VARIATION OF SEDIMENT YIELD IN SANCHUANHE RIVER BASIN IN 1980s than