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目前大型越江隧道的结构设计基本系单独针对单一结构物或其单一方面进行的,如结构的横断面、纵断面、联络横通道、竖井等附属结构物等方面的设计一般是分开考虑的,虽然在初期规划设计时考虑了结构各方面、各局部的相互影响关系,但往往是由专家凭经验定案,尚无一个整体化设计理论作为指导,因此在实际的设计中往往将结构各部位相对孤立起来进行设计,遇到冲突再进行变更,对整个结构往往难以形成优化方案。因此,文章提出了以系统论为框架,利用模糊数学、可靠度理论、专家综合评估法和优化分析等数学理论和工具,以结构整体和局部的关键设计参数的取值及其对目标函数的影响度形成的样品空间进行综合优化分析,考虑水位变化、地质差异、横断面受力、纵向变形、附属结构的修建、偶然荷载及结构稳定性等因素,为大型越江隧道作出整体结构性能好、经济效益高,抗风险能力强的综合最优化设计方案的整体化设计思路。 相似文献
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为提高高速公路路基排水设施性能,通过对高速公路路基排水设施运行过程中出现的一些病害类型进行分析与研究,并据此提出合理的优化方案,包括因地制宜设计合理的高速公路路基排水设施、高速公路路面的排水设施设计、加强高速公路边坡稳固性、加强高速公路路基排水系统的养护、加强预防性养护措施、培养成熟的养护管理队伍六点优化建议,希望这些病害问题能够在实践过程中得到解决,有效提高高速公路路基排水设施的质量,发挥应有的作用。 相似文献
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混凝土湿喷机组广泛应用于铁路、公路、水利水电、市政、矿山、军事等行业地下工程领域。文章针对TKJ系列混凝土湿喷机组举升臂部分进行结构分析、力学性能优化,基于蒙特卡洛法实现了对TKJ混凝土湿喷机组举升臂铰点位置和工作范围的优化,给出了结构受力最优的铰点布局方案;与原方案相比举升臂铰点力在均值和最值上均有所改善,其中举升油缸铰点力最大值和平均值相较原始方案分别减小了23.14%和7.70%。利用AnsysWorkbench的强度分析功能对优化方案进行静强度校核,结果表明,优化方案相较原始方案有较大的安全储备,结构设计更加合理。 相似文献
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为促进核电仪表管阀件的设计,促进设备的国产化,对仪表管阀件在核电站中的设计与应用以及核电站用仪表管件设计的特殊性进行了分析,并结合工程设计经验、现场反馈情况及对照不同堆型项目的类比情况,介绍了目前核电机组仪表管件设计中的重点和难点问题并提出了改进方案。对核级管件国产化的现状进行了分析和展望。 相似文献
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文章在对拟建南宁外环公路大冲邕江特大桥的自然条件、水文、地质、航道等因素进行分析研究的基础上,对原方案大桥主塔承台进行优化设计,并采用有限元软件建立全桥和局部有限元模型进行结构计算分析及验算,确定优化方案的合理性及可行性,为类似工程设计提供参考。 相似文献
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文章结合工程实例,通过旧路评定确定力学参数,建立力学模型,进行力学分析,探索最佳的微裂均质化再生路面方案。结果表明:微裂均质化再生技术适用于整体状况“良”但承载能力一般、断裂板较多的旧水泥混凝土路面;沥青加铺层并非越厚力学性能越好,随着厚度的增加加铺层应力改善作用逐渐减缓,而沥青永久变形量不断增大;基于经济和力学性能综合考虑,10~12 cm厚沥青加铺层+再生旧水泥基层为最佳的微裂均质化再生路面方案。 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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《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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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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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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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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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