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1.
1永定河的特点和特殊的地位与作用 永定河是海河流域北系的主要河流之一,是首都北京的重要防洪、供水河道,它发源于山西省宁武县的桑干河和内蒙古兴和县的洋河,在河北省怀来县朱官屯汇合后始称永定河.永定河流经山西、内蒙、河北、北京、天津5省、市、自治区,在天津北塘入渤海,总流域面积4.7万km2,河道全长680km.永定河自河北省幽州进入北京市界,经门头沟、石景山、丰台、房山和大兴5个区后出市界,在北京市流域面积3 168km2,堤防全长122km.  相似文献   

2.
小浪底工程进水口集中布置,进水塔群由10座进水塔组成,呈"一"字形排列,体积庞大且结构复杂,故对温度控制要求高.洞群衬砌为C30~C70高等级混凝土,且厚度在1~4m之间,温控问题突出.本文从设计、施工及实施效果全面进行了分析、介绍.  相似文献   

3.
延庆地区的湿地保护   总被引:1,自引:0,他引:1  
1湿地的定义及其沿革 对许多人来说,湿地是一个十分生疏的的概念,只是近年来,随着环境问题的突出,人们开始关注湿地."湿地"一词源自英文Wetland,是对地球三大生态系统(海洋、湿地与森林)中的与水发生关联的生态系统的总称.例如无论是天然或人工的湖泊、沼泽、滩涂、水库、蓄洪区、鱼塘、芦苇荡、荷花淀、烂泥坑……更大一些的有海滩、泛洪平原,只要水深不超过6 m的水域,无论咸淡,一律被称做湿地.  相似文献   

4.
永定河是北京的母亲河,它源源不竭的生命之水,在北京的形成、发展、繁荣过程中发挥了不可替代的作用.永定河又是一条汪洋恣肆、难以驯服的河,它暴虐的洪水年复一年地威胁着北京平原的安全.祈求永定成为世世代代生息在这里的人们对这条河的梦想,新中国的建立使这种梦想变成现实,永定河半个世纪安澜无患,写出辉煌的历史新篇章.  相似文献   

5.
元代为避开永定河洪水对都城的威胁,同时也为了使都城有更充足的水源可以利用,将大都城的城址向东北移动到永定河冲击扇脊部.公元1271年,元世祖忽必烈选定在白莲潭(今什刹海)一带建设元大都.为巩固元朝的统治,迫切需要从南方调运大批粮食和其他物资进大都,因而先后疏浚了南北大运河,同时试行海运.元代以前,漕船大多只能抵达通州张家湾.从通州到大都,虽有闸河和坝河可以通漕,但已废多年,坝河河窄水浅运量有限.史料记载:"通州而上,地峻而水不留,其势易浅,舟船不行",主要运输"常从事陆挽,人颇艰之".若"方秋霖雨,驴畜死者不可胜计".  相似文献   

6.
本文结合自己的施工经历,阐述了涎河闸工程闸室底板混凝土的施工技术,从混凝土的配合比、拌制、输送、浇筑、养护及温控等工艺流程上,介绍了混凝土工程施工的质量控制措施.  相似文献   

7.
[本刊综合报道]"5·12"汶川大地震导致四川等地水库、水电站严重受损,水利部领导高度重视.  相似文献   

8.
由于自然、历史、社会等原因,人们对高原冰湖的研究甚少,除险施工更是少之又少。分析西藏定结县皮达湖、龙巴萨巴湖险情的成因与危害,通过对两冰湖除险施工的总结,揭示了高海拔水利工程施工的一些特点、面临的实际问题以及取得的实践经验,并从保护生态及环境的角度出发,对冰湖的保护和治理进行了有益的探索。  相似文献   

9.
2008年1月29日下午5时54分,四川省水电投资经营集团筠连电力有限公司双腾供电所职工彭显松冒着严寒在风雪中抢修电路时,从7m多高的电杆上摔落,不幸英勇殉职,献出了他27岁年轻而宝贵的生命.  相似文献   

10.
岳虎滩水电站增容改造   总被引:1,自引:1,他引:0  
岳虎滩水电站工程始建于1974年,原机组设备较为落后,经多年运行,下游河床内洪水堆积体抬高下游水位严重,且现有发电机组处于超龄服役期,水轮机效率、机组出力明显下降,加之原装机容量偏小,已不能满足电网需求.随着科技进步,在充分利用原有资源、采用新型机组设备条件下,通过对岳虎滩水电站进行综合改造,增加电站容量及机组出力,使电站效益得到大幅提高,同时也达到最大限度地利用水能资源目的.  相似文献   

11.
12.
The paper examines the impact of development activities on water pollution in Malaysia. Hence, the main objective of this paper is not just to examine the trends of development-induced water pollution around the region of the country but to know where the problems are and the policy measures taken by the government. It evaluates the probable causative relationship between problems introduced due to technology employed in water pollution control and governmental policy measures. It examines the relationship between development indicators as sources of pollution and polluted rivers over a period of 12 years. The findings of the paper have shown that despite the policy enforcement actions against the identified sources of water pollution, all the three development indicators (chosen based on those identified sources) still accounted for high percentage of river pollution in Malaysia. The findings of the paper were used to identify the central fact of the location of the problem. Some crucial conclusions of where the problems likely to be, as reflected in the findings, are: (a) the issue of interactive-effects between pollutants that many policy-makers are not aware of. This is when policy measures concentrate only on one source of water pollution; (b) the enforcement strength and/or effectiveness of policy measures themselves; (c) financial constraints to invest in appropriate technology especially sewerage systems for controlling human source of water pollution in the country; as well as those confronting small polluting industries (d) finally, lack of cooperation between government and private business firms to comply with regulatory policies for water pollution control.  相似文献   

13.
A computerized training system for instruction of personnel on the control of turbogenerators during excitation and synchronization of the generator is described; the system is intended for: familiarization with the theoretical bases of generator-operating modes, study of the principles of generator control, improvement of the understanding of the physical bases of instructions regarding control, analysis of possible consequences of errors and violations of instruction requirements, study of emergency modes and the development of anti-emergency measures, and acquisition of experience with generator excitation and synchronization. A basic characteristic feature of the training system is the fact that it includes a complete course of instruction, which covers study of theory, and practical control adjustments under normal and emergency conditions on a trainer, and the knowledge of instructees is tested, and final results are evaluated. The system can be used both in special educational institutions, and also directly at electric power stations in a self-preparation mode. __________ Translated from élektricheskie Stantsii, No. 1, January, 2007, pp. 9–14.  相似文献   

14.
Special features of the structure and properties of the metal of centrifugally cast large-diameter tubes from steel 15Kh1M1F used in hot reheat steam conduits of high-power generating units are discussed. The metal of the tubes in the initial state is shown to possess structural heterogeneity primarily represented by segregation bands. The segregation bands are responsible for scattering of the mechanical properties and a 5 – 10% decrease in the long-term strength in the initial condition. The decline of the long-term strength intensifies with the propagation of the segregation over the cross section of the tubes. The segregation lowers the stability of the structure and properties of the tubes in operation at a high level of long-term plasticity. By reducing the degree of segregation in centrifugally cast tubes the time of their operation in steam conduits can be increased to 200,000 h.  相似文献   

15.
Results of investigations of the dependence of the percentage of voids on the shear force of a layer of ash, on the basis of which the design principle of the subassembly for the feed of ash to a transport pipeline is developed, are examined for optimization of ash flows in a pulsed regime. The schematic of a system of pulsed pneumatic transport of ash from the bins of ash collectors, and results of measurements during experimental operation of the system, as well as relationships for the calculation of its dynamic parameters are presented. Conclusions concerning the high reliability of the removal and pneumatic transport of ash over a distance of more than 80 m with minimal air consumption are drawn on the basis of results of the experimental operation. __________ Translated from élektricheskie Stantsii, No. 6, June 2007, pp. 17–20.  相似文献   

16.
Analysis of the operational experience and diagnostics of turbogenerators is used to show that the actual life of a turbogenerator should not be treated as the decisive factor for making judgment on the necessity of its replacement or updating. The efficiency of diagnostic service and inspection of long-operating and newly commissioned turbogenerators is proved on the basis of results of a study of over 100 turbogenerators of various types and capacities. It is shown that timely detection and removal of flaws in the initial stage of their development is a substantial factor determining the possibility of extending the service live and ensuring reliable operation of turbogenerators. __________ Translated from élektricheskie Stantsii, No. 4, April 2006, pp. 51–54.  相似文献   

17.
本文介绍码头结构整体空间计算,码头面板在集中荷载作用下的有限分布宽度和弯矩分配系数试验,大跨度大空心板的研制和试验,有限棱条法计算,叠合拼板试验和面板横向配筋研究等。  相似文献   

18.
应用马尔文MS2000激光粒度分析仪分析河流泥沙颗粒   总被引:9,自引:0,他引:9  
水位、流量、泥沙测验和分析,是水文工作的3大基本要素。当前,水位、流量的测验,通过引进新的设备,已取得一定的成效,但河流泥沙颗粒的测验,依然应用传统的方法。自引进了MS2000激光粒度分析仪后,泥沙颗粒的测验和分析手段得到了质的飞跃,在此,就MS2000激光粒度分析仪的特性及实际应用进行分析和介绍。  相似文献   

19.
基于武汉地铁名都站深基坑工程与水文地质勘察资料,建立了三维工程地质仿真计算模型。依据名都站深基坑开挖支护方案,利用有限元软件MIDAS的摩尔-库仑本构模型,对武汉地铁名都站深基坑施工过程中,不同施工工序下每步开挖之后,基坑的变形情况做仿真模拟计算,并对比分析其对基坑稳定性的影响。结果表明:基坑围护结构的变形情况与施工工序有很大的关系,施工工序越合理,上部土体变形越小,反之越大。因此,在基坑工程的施工过程中,要注重施工步骤的划分与合理安排,从而保证基坑工程的安全。研究成果为以后武汉地区基坑工程的施工设计提供了值得借鉴的经验。  相似文献   

20.
堵凤春 《中国水利》2011,(19):44-46
北京市怀柔区在创建节水型社会实践中,通过采取行政、经济、法律、宣传、技术等多种手段,全方位开展节水工作,为确保首都北京的供水安全作出了贡献。针对水资源短缺形势严峻、地下水水位严重下降、非常规水源利用率较低等问题,怀柔将在节水型社会建设试点工作中,建立健全节水型社会制度和管理体系,进一步加强用水总量控制与定额管理的实施,计划到2013年初步构建节水型社会框架。  相似文献   

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