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关角隧道位于青藏铁路西格段,是我国目前最长的越岭铁路隧道.针对关角铁路隧道复杂地质的特点,提出了辅助坑道的设计原则.通过对斜井、竖井进行分析比较,确定斜井作为辅助坑道.文章详细地介绍了斜井的断面、内轮廓以及平导内轮廓、施工横通道内轮廓,制定了隧道施工综合成洞指标和指导性施工组织方案.通过对三个施工方案的分析比选,推荐了10座斜井加局部平导方案. 相似文献
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通过对乌鞘岭特长隧道辅助坑道的比选,重点论述了施工斜井的预设计情况,以求充分发挥施工斜井在特长隧道施工中的重要作用,尽快建成特长隧道. 相似文献
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桃树坪隧道穿越富水粉细砂地层,施工难度很大,尤其是斜井进正洞的挑高段施工风险更高.通过对四种方案在施工工序、支护形式及体系转换等方面的比选,最后选择采用导洞爬高进入正洞双侧壁导洞高度进行导洞施工、后进行中间部分施工的设计方案,顺利完成了隧道施工.文章详细介绍了四种比选方案及方案实施效果. 相似文献
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乌鞘岭特长隧道方案设计 总被引:3,自引:0,他引:3
乌鞘岭隧道为目前我国最长的铁路隧道,长20.05 km,其地质条件复杂、工期极其紧张、工程规模巨大,引起了国内外地下工程界的瞩目.文章通过越岭隧道限坡、长度、单双洞方案比选介绍了乌鞘岭特长隧道方案选择情况;并从隧道施工方案、防排水、运营和施工通风等方面较为系统地介绍了隧道的设计概况. 相似文献
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公路隧道通风设计软件(VDSHT)的编制及特点 总被引:2,自引:0,他引:2
通风技术是21世纪公路隧道发展的关键技术之一,但目前国内的通风计算仍以手工为主,工作效率较低,不便于多方案的评价比选.文章介绍了一套隧道通风设计软件(VDSHT)[2],它不仅可以进行各种纵向、半横向、全横向和混合通风方式的计算,而且可以进行多种通风方案的评价比选. 相似文献
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通风导洞中隔墙一般采用技术较为成熟的混凝土中隔墙,但存在表面粗糙、工艺复杂、施工进度不易控制等缺点,无法适用于风道较为复杂的工程。文章以东天山隧道1号斜井为依托,提出了节能型全拼装式钢波纹板中隔墙技术,通过数值模拟以及理论计算的方法验证其在单洞四风道通风斜井中的可行性。研究结果表明:钢波纹板式中隔墙增大了斜井有效通风截面积,断面风速降低约5.3%,同时大幅减小通风斜井内的沿程阻力,仅为既有混凝土墙方案的17%左右;拱顶变形及二次衬砌混凝土结构受力均远低于结构安全限值。该技术克服了传统钢筋混凝土中隔墙的缺点,在满足隧道通风防灾要求的同时,改善了隧道施工环境,且施工工期可缩短为原方案的三分之一。 相似文献
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乌池坝特长公路隧道通风方案设计 总被引:4,自引:1,他引:4
文章简要介绍了乌池坝特长公路隧道的工程概况,对目前最为常用的全射流通风以及斜、竖井加射流风机组合的分段纵向通风方式进行了对比、分析和研究,并充分考虑了正常运营、交通阻塞、火灾和换气四种不同工况下隧道内气流组织、通风及其控制等要求,提出了推荐方案:右线采用斜井集中排出式 竖井送排式 射流风机纵向通风,左线采用斜井集中排出式 射流风机纵向通风。本通风方案采用了一井两用的设计思路,即左线斜井同时对左线隧道和右线隧道进行集中排风;此外,考虑左线入口段火灾时的排烟,从右线竖井处设置了专用排烟通道连接左线。在满足通风要求的基础上,重点研究了通风运营成本及运营安全、火灾排烟及火灾通风控制等关键问题。 相似文献
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Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD). An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip. It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links. 相似文献
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天然气自动计量系统有多种组态软件,由于软件的不相通性,造成了计量系统数据采集的通用性差、数据传输与入库的时效性差、数据利用的可靠性低.结合各组态软件的实际情况,从设计上充分利用Oracle大数据处理能力以及Partition(分区表)的特性,实现历史数据的存储,应用WebService与COM+数据访问组件提供多层数据访问架构,采用OPC与DDE工业数据交换协议,实现了各站场计量数据的实时上传,为连续数据采集和实时监控提供了可能,节约了改造成本. 相似文献
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This paper estimates the efficiencies and productivity changes of 12 international airports in the Asia-Pacific region based on data from 1998 to 2006. We apply stochastic frontier analysis (SFA) to compute efficiency estimates and use the Malmquist productivity index (MPI) to analyze productivity changes. We use the SFA model with a translog-type production function after testing the statistical hypotheses. According to the results of the SFA hypothesis tests, airports have experienced a technological regression; the deviations from the efficiency frontier are caused more by technical inefficiency than random noise. However, the inefficiency was found to decrease. The MPI reveals a declining trend resulting more from technological change than from efficiency change, with a decrease in inefficiency. Taken together, both the hypothesis tests and the MPI not only provide consistent conclusions, but also suggest that airports should concentrate on technological progress. 相似文献
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介绍了城市轨道交通工程中杂散电流不同的监测系统的构成,分析了集中式、分散式和智能型等监测系统的配置和功能,以及智能型实时在线监测系统的重要意义,为轨道交通工程杂散电流监测系统的选择与应用提供参考。 相似文献
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明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。 相似文献
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《Transportation Research Part A: General》1991,25(6):407-418
The main deficiency of most current modeling approaches to transportation can be identified as neglect of the integration of existing geographical knowledge in regard to the ex ante transport/land use modeling approaches, with its focus on territorial dynamics and theory development. This paper addresses this aspect of the problem by introducing a theoretical and methodological framework for the analysis of the interrelationship between land uses. The analysis attempts to determine to what extent the functional land use in a city can be considered an ordered pattern. The order sought does not rely on purely spatial configurations, but on the correlation of transportation and land use. The first section of this paper focuses on theoretical considerations. It stresses the fact that conventional approaches do not apply in the present context. It then suggests an alternative based on areas of influence and measured in terms of level of attractance of land uses. The second describes a procedure based on this alternative following the remarkable contribution of Hanjoul, Beguin and Thill. An application of this procedure to the analysis of Shanghai is then examined. Finally, an evaluation of the strategies for optimizing the interrelationship between land uses is presented. The paper concludes with a possible research agenda. 相似文献
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Joseph N. Prashker 《Transportation》1979,8(4):329-346
Reliability of travel modes was found to be the most important characteristic of transportation systems in several attitudinal investigations of individual travel behavior. This paper represents the first part of a research effort aimed at gaining a better understanding of the characteristics of reliability of transportation modes in urban travel. In this research, reliability characteristics are identified; their importance relative to each other is assessed, and an insight into possible structure of an objective reliability index is discussed. The research is based on perceived values of reliability, which were identified through a large attitudinal survey conducted in the Chicago metropolitan area. 相似文献