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41.
It is sometimes argued that standard state-of-practice logit-based models cannot forecast the demand for substantially reduced travel times, for instance due to High Speed Rail (HSR). The present paper investigates this issue by reviewing the literature on travel time elasticities for long distance rail travel and comparing these with elasticities observed when new HSR lines have opened. This paper also validates the Swedish long distance model, Sampers, and its forecast demand for a proposed new HSR, using aggregate data revealing how the air–rail modal split varies with the difference in generalized travel time between rail and air. The Sampers long distance model is also compared to a newly developed model applying Box–Cox transformations. The paper contributes to the empirical literature on long distance travel, long distance elasticities and HSR passenger demand forecasts. Results indicate that the Sampers model is indeed able to predict the demand for HSR reasonably well. The new non-linear model has even better model fit and also slightly higher elasticities. 相似文献
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Raimund K. Herz 《运输规划与技术》2013,36(4):311-328
The rediscovery of the bicycle by the public, by politicians and by professional urban transportation planners as a mode of transport which is perfectly in harmony with the goals of environmental protection, energy saving and personal fitness has stimulated this empirical study on the actual use of the bicycle by various population groups for obligatory and discretionary trip purposes. The influence on bicycle usage of such factors as age, education, car availability, residential density and town size, topography and time of year is analysed in this paper for selected population groups. For housewives from motorized households logit‐models were designed and calibrated to model their modal choice for shopping trips with special references to the bicycle. From the empirical results, the groups with the largest potentials for cycling are identified and the extent to which the potentials could be activated by specific policies is discussed. The research is based on a large sample held to be representative for the Federal Republic of Germany in 1976 and is supplemented by more recent surveys in selected German cities conducted by SOCIALDATA Munich. 相似文献
44.
Waterseepageofakarsttunnelsectioninsoilsurroundingrockispronetosurfacesubsidence.Considering the settlement caused by descending of water level due to water leakage, a method of surface settlement estimation under steady seepage of phreatic water was proposed. Based on the seepage and consolidation theory, the changes of dead-weight and seepage effective stress of soil unit in surrounding rock was analyzed in condition of water seepage, and the settlement zone of surrounding rock was divided by taking the funnel curve of precipitation as the boundary line. A two-dimension plane was established based on the excavation cross section and the estimation formula for surface settlement due to seepage effect was deduced by means of double integral. On the basis of Yaozhai tunnel of Liuzhai-Hechi Expressway in Guangxi Zhuang Autonomous Region, the surface settlement of soil surrounding sec⁃ tion was predicted by field measurement and formula estimation respectively. Facts and figures show that the mea⁃ sured values are mainly consistent with the estimation ones, while the measured values are larger than the estima⁃ tion ones within the scope 3 m away from the excavation face along the horizontal radial direction. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献
45.
以新疆乌鲁木齐“世纪花苑”三期工程人防地道为例,运用快速拉格朗日差分分析程序,通过逐渐调整上部荷载大小,使其达到临界状态下的数值模拟方法,系统分析不同影响因素(如洞跨、顶拱高跨比、顶板厚度、荷载范围等)对人防地道顶板最大安全荷载的影响及相关变化规律。结果表明,顶板最大安全荷载与洞跨及荷载范围成反比,而与顶拱高跨比、顶板厚度和荷载偏心率成正比。在此基础上,用数理统计方法得出能综合考虑各影响因素下顶板最大安全荷载的预测方程。 相似文献
46.
对锰铜合金螺旋桨表现热涂涂层的性能进行了试验,并对采用热喷涂涂层防止螺旋桨腐蚀的可行性进行了研究。试验结果表明:采用高速氧燃料喷涂技术形成的Cu95超涂层人有优良的耐空蚀,耐海水腐蚀性能,可作为锰铜系合金螺旋桨表面的防腐涂层。 相似文献
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分析了影响作业能力的主要因素及其力学物理过程,在此基础上,探讨了提高土方机械对土壤作业能力的途径与方法。 相似文献
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The CAMCAT oil spill forecasting system is presented in this paper, and an evaluation of the impact of errors in the forcing fields over its forecasts is carried out. The system is formed by several independent modules which provide forecasts of winds, currents and waves to an oil spill module which predicts the evolution of the spill.The typical twin-experiments experience is used paying special attention to a realistic characterization of the errors when perturbing the forcing fields. The results suggest that errors in the wind and current fields are the main limiting factor for the quality of the oil spill forecasts. The pollutant identification is also crucial to determine the final vertical position and characteristics of the product. 相似文献
50.
在我国的西部,尤其是西北地区修筑公路时,不可避免地会遭遇到大范围的黄土路基,而这其中大部分是具有湿陷性的黄土.因此,必须充分掌握湿陷性黄土的工程地质性质,在施工中对湿陷性黄土进行相应的工程处理.以具体工程为背景,介绍了湿陷性黄土的工程处理措施,使其能够满足设计的各项要求,保证公路工程施工和运营阶段的质量. 相似文献