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文章结合世界上海拔最高的青藏铁路风火山隧道的施工实践,从工程设计、机械的选型与配套、制氧、供氧系统的研制及应用、冻土、冻岩光爆、保温、控温、防水保温层的铺设、信息化施工和工序网络管理等方面,介绍了冻土隧道施工新技术。 相似文献
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文章针对我国采用矿山法施工的隧道机械现状进行分析,提出了各个施工工序,如超前地质预报、超前支护、开挖、装碴与运输、初期支护、防排水、衬砌、通风等的机械化施工设备配套的建议。 相似文献
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文章结合工程实例,从节段箱梁预制施工工艺、预制区的建设、配套设施、工序衔接等方面,阐述了短线匹配法节段梁预制施工技术及质量控制要点,以期为类似工程提供借鉴。 相似文献
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济南至莱芜高速公路工程项目中的隧道均设计成超大型断面,施工难度和危险性都比较大,安全施工和规范施工成为承建单位的重点和难点.介绍了单幅长度达近5km的蟠龙隧道的施工工序、施工方法,使用该方法实现了隧道围岩开挖工序无塌方、无人身伤亡和无重大事故贯通. 相似文献
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雅泸高速公路大相岭隧道2#通风斜井存在距离长、断面大、坡度陡、涌水量大等施工难题,难以完全按照传统的施工方法进行施工.在确保安全的前提下,通过对大相岭隧道2#通风斜井各道施工工序的实践论证,合理地选择了有轨运输配套设备,建立了低压接力泵站与移动泵站相结合的排水系统.采用5 t慢速卷扬机和3×4滑轮组组成的牵引系统牵引大吨位衬砌台车.有效地解决了长距离、大倾角、曲线、富水斜井掌子面的出碴、排水和二次衬砌等问题,加快了隧道施工进度,减少了工程投资,拓展、丰富了斜井施工领域,对促进我国乃至世界斜井施工技术发展具有重要意义. 相似文献
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文章采用有限元计算的方法对东楼隧道施工中病害进行分析,通过不同施工工序给隧道结构体系所带来力学上的差异,揭示了施工工序对隧道结构体系稳定的重要性,同时也表明理论分析计算在隧道设计和施工中占有重要的地位. 相似文献
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本文依托重庆火凤山隧道工程的修建开展研究,通过数值模拟,分析了不同施工工序对各断面形状的影响效果,并结合各断面形状所采用的施工工法,提出合理的施工工序.结果表明:(1)对于采用CD法施工的17 m特大断面段与21 m特大断面段而言,优化后的施工工序对围岩位移与塑性区的控制效果较为有限,但能有效改善开挖过程中初期支护应力的应力集中现象、降低应力值,且应力集中分布的位置有所差异.同时,通过优化施工工序能够减小支护结构左右侧应力分布不均匀程度,改善隧道开挖后支护结构的受力状态;(2)通过采用左右交互开挖的施工工序,24 m特大断面段与30 m特大断面段的围岩位移与支护结构应力均有所减小,同时对围岩的扰动也有所下降,但改善效果不及CD法明显.整体而言,优化后的施工工序对24 m特大断面段与30 m特大断面段隧道开挖较为有利,建议采用优化后的施工工序进行施工. 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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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
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本文阐述了混合动力列车的技术特点及其相应优势与劣势,同时介绍了其在国内外的研究动向,并对其应用前景进行了展望。尽管该类新型铁道车辆的续航能力、电池寿命以及成本等相关问题目前仍有待改善,但以其对城市环境的美化作用与优越的舒适驾乘性能,以及高效节能、绿色环保的显著优势,依然不失为一类充满前景的新型轨道交通运输方式。 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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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