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为了加强公路结构的强度与刚度,当前的公路建设一般采用半刚性基层加柔性面层的结构,然而与此同时也使得公路存在容易干缩和温缩造成的裂缝问题,随着雨水的不断渗入,必然使公路基层受到侵蚀,导致结构性破坏.为解决这些问题,本文以某公路工程为例,就公路沥青路面工程中沥青路面裂缝及其病害进行了分析,并就相关工程的养护施工及检测进行了... 相似文献
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针对目前国内半刚性基层沥青路面普遍出现的早损现象,吸收国外先进的设计理念,合理考虑超载影响,结合高速公路路面维修实例,对柔性路面基层进行了有益的探讨,寻找适宜的路面结构,延长沥青路面全寿命面使用周期. 相似文献
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在旧路的改造工程中采用大碎石沥青混合料柔性基层能够充分满足结构强度和高温稳定性要求,同时可起到路面结构排水的作用,并且在一定程度上可以有效地防止反射裂缝的出现。文章结合具体的旧路改造工程实例,介绍大碎石沥青混合料柔性基层施工工艺及质量控制与检验方法,以期对类似工程起到借鉴作用。 相似文献
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广佛高速公路沥青路面破坏分析与结构优化 总被引:1,自引:0,他引:1
以广佛高速公路路面状况调查和评价为背景,介绍了半刚性基层沥青路面结构破坏机理,对半刚性基层沥青路面的破坏原因进行了分析.引入永久性路面结构概念,提出了沥青路面结构优化方向. 相似文献
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在公路工程施工中,沥青路面冷再生技术有重要作用,为提高该技术应用效果,结合工程实例对公路工程沥青路面冷再生技术的应用进行研究。分析了测量放样、旧路面预处理、原材料选择、撒布水泥与乳化沥青、再生路面整形、碾压与养护等沥青路面冷再生技术应用要点。根据检验结果可知,通过合理控制上述要点,该项目的再生基层多项指标满足设计要求,沥青路面结构更加稳固,可保障车辆通行安全,可为同类工程提供参考。 相似文献
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文章拟定3种混合式基层沥青路面结构,通过BISAR软件进行路面应力、应变计算分析,研究不同混合式基层路面结构的力学性能。研究结果对混合式基层沥青路面的设计、施工及养护具有一定的指导意义。 相似文献
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Ingmar Andrasson 《先进运输杂志》1998,32(1):23-34
A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996. 相似文献
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AbstractDespite a concentration of container traffic in the southeast of the UK over the last few decades, regional ports are attempting new development strategies to capture or retain specific traffic segments. These include intra-European short-sea traffic and a potentially increasing feeder market. These trends are reflected in the movement of different container types, which result in a number of planning challenges related to changing infrastructural and operational requirements. This paper uses highly disaggregated data on container type movements to address three issues that can inform these planning challenges. First, the imbalance of trade resulting in empty container repositioning; second, the requirement for gauge-cleared rail routes to cater for the increasing proportion of high-cube containers; and third, the specialisation of European short-sea traffic at secondary UK ports. The results reveal the disproportionate repositioning of empty containers at Scottish ports and the importance of 45?ft, high-cube and pallet-wide containers at regional ports, highlighting their focus on intra-European short-sea traffic and raising difficulties relating to their lower quality of landside infrastructure (particularly rail) in comparison to the large south-eastern ports. The potential repercussions on hinterland infrastructure development raise questions about both public and private sector responses to regional port development. 相似文献
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管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一(各因素的分值范围都是0~100分),为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。 相似文献
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The concept of accessibility has acquired numerous meanings along multiple dimensions during the century of its evolution. This essay argues for the salience of two dimensions: application-based and definition-based. In its application, accessibility has incorporated positive and normative dimensions which have varied in prominence over time. In its definition, accessibility has varied between a mode of evaluation incorporating measured mobility and proximity, on the one hand, and a predefined market basket of urbanist improvements to transportation and land use systems, on the other. Advocates of the accessibility shift should emphasize both the measured approach to accessibility and accessibility’s normative side. 相似文献
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The big paradigm for cities nowadays is to study the movement of pedestrians at the interface between metro and bus systems – metro–bus interchanges. When these interchanges are not well designed, walking is inefficient and can be unsafe for pedestrians. This paper analyses, by means of a pedestrian microsimulation model, metro–bus interchange spaces in order to propose planning guidelines for the city of Santiago de Chile. Specific objectives are (1) to identify the variables that provide efficiency and safety in those spaces; (2) to simulate different scenarios using the pedestrian simulation model LEGION; (3) to propose planning and design guidelines for pedestrian spaces at metro–bus interchanges; and (4) to contrast the recommendations in the recently opened terminal station on Line 1 of Metro de Santiago: Los Dominicos Station. 相似文献
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Nicholas B. Taylor 《运输规划与技术》2018,41(1):37-57
ABSTRACTPredicting the risk of traffic demands and delays exceeding critical limits at road junctions, airports, hospitals, etc., requires knowing how both mean and variance of queue size vary over time. Microscopic simulation can explore variability but is computationally demanding and gives only sample results. A computationally efficient approximation to the mean is used in many modelling tools, but only empirical extensions for variance in particular situations have been available. The paper derives theoretical formulae for time-dependent and equilibrium variance, believed to be novel and to apply generally to queues covered by the Pollaczek–Khinchin mean formula, and offering possible structural insights. These are applied in an extended approximation giving mutually consistent mean and variance estimates with improved accuracy. Tests on oversaturated peak demand cases are compared with Markov probabilistic simulation, demonstrating accuracy (R2?>?0.99) for typical random, priority-like (M/M/1) and traffic-signal-like (M/D/1) queues. Implications for risk analysis, planning and policy are considered. 相似文献