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381.
水泥混凝土路面配合比设计阶段是保证路面实体强度的首要阶段,也是十分重要的阶段。笔者依据多年的经验并结合多条高速公路的施工监理实践,在广梧高速公路河口至平台B段的施工监理过程中,针对水泥混凝土路面配合比设计阶段,从原材料各个主要因素入手对配合比进行单因素优化设计,找出原材料影响水泥混凝土强度(主要是抗折强度)的关键因素,... 相似文献
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Spatial impacts of road pricing: Accessibility, regional spillovers and territorial cohesion 总被引:1,自引:0,他引:1
Ana Condeço-MelhoradoJavier Gutiérrez Juan Carlos García-Palomares 《Transportation Research Part A: Policy and Practice》2011,45(3):185-203
Road pricing policies are gaining prominence in EU countries. These policies have positive impacts leading to mobility patterns which are socially and environmentally more desirable, but they also have negative impacts. One negative impact is to be found in regional accessibility, due to the increase in generalized transport costs. This study presents a methodology based on accessibility indicators and GIS to assess the accessibility impacts of a road pricing policy. The methodology was tested for the Spain’s road network considering two road pricing scenarios. It enables not only the more penalized regions to be identified but also negative road pricing spillover effects between regions. These effects are measured in terms of accessibility changes occurring in one region produced by charges implemented in another region. Finally, the study of accessibility disparities (by calculating inequality indexes for each of the scenarios considered), provides policymakers with useful information regarding the impact of road pricing policies from the point of view of territorial cohesion. 相似文献
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Multi-objective optimization of a road diet network design 总被引:1,自引:0,他引:1
Keemin Sohn 《Transportation Research Part A: Policy and Practice》2011,45(6):499-511
The present study focuses on the development of a model for the optimal design of a road diet plan within a transportation network, and is based on rigorous mathematical models. In most metropolitan areas, there is insufficient road space to dedicate a portion exclusively for cyclists without negatively affecting existing motorists. Thus, it is crucial to find an efficient way to implement a road diet plan that both maximizes the utility for cyclists and minimizes the negative effect on motorists. A network design problem (NDP), which is usually used to find the best option for providing extra road capacity, is adapted here to derive the best solution for limiting road capacity. The resultant NDP for a road diet (NDPRD) takes a bi-level form. The upper-level problem of the NDPRD is established as one of multi-objective optimization. The lower-level problem accommodates user equilibrium (UE) trip assignment with fixed and variable mode-shares. For the fixed mode-share model, the upper-level problem minimizes the total travel time of both cyclists and motorists. For the variable mode-share model, the upper-level problem includes minimization of both the automobile travel share and the average travel time per unit distance for motorists who keep using automobiles after the implementation of a road diet. A multi-objective genetic algorithm (MOGA) is mobilized to solve the proposed problem. The results of a case study, based on a test network, guarantee a robust approximate Pareto optimal front. The possibility that the proposed methodology could be adopted in the design of a road diet plan in a real transportation network is confirmed. 相似文献
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空隙率的大小对大空隙沥青混合料的渗透性及力学性能具有很大影响,透水铺面应根据用途选择合适的空隙率,在一定的水头(降雨强度)下利用空隙模型确定的目标空隙率进行混合料配合比设计.结果表明,空隙模型确定的目标空隙率可为混合料的配合比设计提供理论指导,提高了传统设计方法的工作效率和准确性. 相似文献
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介绍高等级公路建设中,施工前、施工中、施工后三个阶段对沥青混凝土路面平整度的质量控制,可为类似工程提供参考。 相似文献
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通过对路面铣刨机的结构及工作原理的理论分析,针对路面铣刨机在正常作业过程中零件磨损的现象,提出路面铣刨机械的养护措施,对提高施工质量和效率,降低施工成本有着重要的意义。 相似文献