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《Transportation Research Part A: General》1987,21(1):39-46
This paper deals with driver behavior while travelling on and merging from acceleration lanes. Two possible groups of drivers were identified: drivers who always perform the merging maneuver during the second part of the acceleration lane, regardless of whether an appropriate gap or lag was available to them previously. Three components of the aggregated delay for the merging process were suggested and evaluated. A method of estimating the random delay and travel time on acceleration lane was proposed and evaluated against an aggregated empirical data obtained on three freeway acceleration lanes. An evaluation of the contribution of the ramp volume to the traffic delay was also performed and discussed and a graph which may be of practical use for road and traffic engineers in assessing the expected influence of various ramp and freeway volume combinations is presented. 相似文献
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关于新意法隧道设计的几点建议 总被引:1,自引:0,他引:1
在引进国外先进的隧道修建技术(新意法)时,不应生硬地照抄、照搬,而应在引进和消化吸收的基础上,结合我国的实际情况,不断改进、创新,逐步探索并形成具有中国特色的隧道设计、施工理论和先进、适用的隧道施工方法,以进一步提高我国隧道修建技术水平。文章针对新意法特点,就复杂地质条件下隧道选线、衬砌支护参数的选定及施工方案提出了具体的建议,可为新意法在我国的推广应用提供参考。 相似文献
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《Transportation Research Part A: General》1987,21(6):401-410
This study evaluates a new approach for reducing delay, and consequently improving level of service and safety on long upgrades on two-lane rural roads. This is the systematic provision of overtaking lanes, termed passing-climbing lanes (PCL), to improve traffic flow, safety, and capacity. The traffic impact of such lanes is analyzed for various grades, traffic volumes, and lane configurations by means of a simulation model developed for this study. Results show that this concept could provide substantial flow benefits—reduction in delay and in passenger-car platooning—with implications for better safety. Although the reduction in delay is found to be more pronounced as volume increases, these results may be obtained even with a small percentage of passing-climbing lanes. A model predicting average relative delay, formulated and calibrated on the basis of the simulation output, explains 95% of the observed variability. The economic advantages of the concept in optimizing the distribution of a limited budget among several sites, in staging construction over several years, and in adapting highway investment to traffic-demand variations are also discussed. 相似文献
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文章对膨胀土的物理力学进行了分析,解释了路基病害形成的机理,提出了相应处理措施,最后引用小河-安康高速公路膨胀土处理的实例验证了处理措施的合理性. 相似文献
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通过模型试验对高速铁路列车通过带有辅助坑道的隧道时形成的气压波动进行模拟,并对试验结果进行分析,研究高速铁路隧道辅助坑道的位置、长度及断面面积对瞬变压力的影响.试验结果表明,辅助坑道的位置不同,即反射界面的位置不同,会导致产生膨胀波的叠加位置发生变化,从而对列车上空气压力波动会产生有利或不利影响;根据叠加原理,可以得出影响隧道瞬变压力的长隧道中辅助坑道最有利和不利位置.通过压力波动曲线比较可知,辅助坑道的长度对隧道内瞬变压力的影响不大;但辅助坑道的断面积不宜过大,否则会产生不利影响. 相似文献
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文章以某大桥柔性桥塔结构环境振动测试为例,阐述了桥塔结构环境振动测试的一般步骤和技术细节,并采用时域随机子空间识别方法(SSI)对桥塔动力特性(振动模态参数)进行了识别分析。经验证,识别分析结果与理论计算值能较好吻合。 相似文献
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强震产生的地震波会对路基边坡造成巨大的破坏,严重摧毁道路、阻碍救援。文章阐述了强震动作用对路基边坡的破坏机理,分析了强震作用下产生的"地震波效应-地震力作用于边坡体-坡体破坏"波动袭击链的链式效应。 相似文献