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141.
阐述了黄土的分布与性质,对黄土路堤沉降的机理及原因进行了分析.分析比较了基于实测资料预测黄土路堤工后沉降值的实用模型,包括指数模型,幂函数模型,双曲线模型.以指数模型为例,根据已建成某大坝实测数据,确定了预测模型的参数. 相似文献
142.
通过对波动传递函数的逆傅里叶变换建立脉冲响应函数的解析表达式,在仅已知不规则波波面过程线的情况下,利用脉冲响应函数与已知波面序列的卷积求得不规则波的速度场,并计算不规则波浪序列引起的水质点速度、加速度。通过与线性波浪叠加法的对比验证了方法的正确性,并应用Morison方程计算小尺度圆柱上的不规则波浪力。对不规则波浪力进行频谱分析得到:在非线性较弱时,脉冲响应法求得的波浪力谱与线性谱分析法的波浪力谱较为接近。随着波浪非线性的增强,脉冲响应法求得的速度力谱与线性谱分析法相比峰值不断增大,在低频和高频处能量增多,在主要能量区的谱宽也不断增加,而惯性力谱与线性谱分析方法结果基本相同。 相似文献
143.
城市新区道路横断面规划设计研究 总被引:1,自引:0,他引:1
道路系统的建设是引导城市新区开发、改善投资环境的重要措施。城市道路横断面作为道路交通功能实现的重要载体,其合理规划设计有利于保障道路安全畅通,提高资源利用效率,实现城市社会经济的良性发展。 相似文献
144.
在对南京市交通量与经济发展指标统计分析的基础上,运用向量自回归模型——VAR模型进行分析,通过采用协整检验模型、Granger因果关系检验模型和脉冲响应函数等分析,得到交通运输与经济发展之间的关系,并给出相应的建议. 相似文献
145.
《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(3):362-389
A vertical vehicle–track coupled dynamic model, consisting of a high-speed train on a continuously supported rail, is established in the frequency-domain. The solution is obtained efficiently by use of the Green's function method, which can determine the vibration response over a wide range of frequency without any limitations due to modal truncation. Moreover, real track irregularity spectra can be used conveniently as input. The effect of the flexibility of both track and car body on the entire vehicle–track coupled dynamic response is investigated. A multi-body model of a vehicle with either rigid or flexible car body is defined running on three kinds of track: a rigid rail, a track stiffness model and a Timoshenko beam model. The results show that neglecting the track flexibility leads to an overestimation of both the contact force and the whole vehicle vibration response. The car body flexibility affects the ride quality of the vehicle and the coupling through the track and can be significant in certain frequency ranges. Finally, the effect of railpad and ballast stiffness on the vehicle–track coupled vibration is analysed, indicating that the stiffness of the railpad has an influence on the system in a higher frequency range than the ballast. 相似文献
146.
将发货人满意度和港口兼容性引入发货人效用函数,放宽传统Hotelling竞争模型中港口定位必须局限于发货人分布空间的假设,通过拓展线性Hotelling模型来研究发货人满意度和港口兼容性与港口选址、收费的关系。研究表明:发货人满意度在港口市场竞争中具有关键作用;同时,发货人满意度相对较强的港口并不一定具有市场竞争优势,市场竞争形成市场份额的最终格局取决于发货人满意度的相对强弱程度。 相似文献
147.
Abstract The estimation of annual average daily traffic (AADT) is an important parameter collected and maintained by all US departments of transportation. There have been many past research studies that have focused on ways to improve the estimation of AADT. This paper builds upon previous research and compares eight methods, both traditional and cluster-based methodologies, for aggregating monthly adjustment factors for heavy-duty vehicles (US Department of Transportation Federal Highway Administration (FHWA) vehicle classes 4–13). In addition to the direct comparison between the methodologies, the results from the analysis of variance show at the 95% confidence level that the four cluster-based methods produce statistically lower variance and coefficient of variation over the more traditional approaches. In addition to these findings – which are consistent with previous total volume studies – further analysis is performed to compare total heavy-duty monthly adjustment factors, both directions of traffic, with direction-based monthly adjustment factors. The final results show that the variance as well as the coefficient of variation improve on average by 25% when directional aggregate monthly adjustment factors are used instead of total direction. 相似文献
148.
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150.
L. Auersch 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2005,43(9):671-695
A combined finite-element boundary-element method is presented in detail to calculate the dynamic interaction of the railway track and the underlying soil. A number of results are shown for ballasted and slab track, demonstrating the influence of the stiffness of the soil and the rail pads on the vertical compliance of the track. The compliance of the track is combined with a simple model of the vehicle giving the transfer function of vehicle-track interaction. An experimental verification of the theoretical results is achieved by harmonic and impulse excitation with and without static (train-) load and by combined measurements of train-track-soil interaction. A clear vehicle-track resonance is found for the slab track with elastic rail pads and for higher frequencies at highspeed traffic, the dynamic axle loads due to sleeper passage are reduced. 相似文献