栈桥式平移法换架高速铁路简支箱梁技术研究

随着我国高速铁路桥梁的快速发展,各种灾害对其造成破坏的可能性增高。为了能够有效应对未来高速铁路桥梁灾后的快速保障需求,重点研究将来高速铁路桥梁遭受灾害损毁破坏后,在通过抢修钢梁保证临时限速通车的情况下,采用栈桥式平移法实现新制混凝土箱梁和临时抢修钢梁换装施工的技术方案。主要研究内容包括:总体技术方案、施工场地布置方案、施工设备的设计方案和换架梁施工工艺等,并总结该项技术的关键技术要点和方案的适应性。通过研究说明,栈桥式平移法是一种安全可靠、成本低廉、快速有效的换架梁施工技术,有助于推动我国高速铁路桥梁灾后应急保障技术的发展,并为同行提供有价值的参考。     

Prohibited–permitted right-turn phasing strategy based on capacity analysis of right-turn movements

In traffic-crowded metropolitan areas, such as Shanghai and Beijing in China, right-turn vehicles that operate with a permitted phase at signalized intersections are normally permitted to filter through large numbers of pedestrians and bicycles. To alleviate such conflicts and improve safety, traffic engineers in Shanghai introduced a prohibited–permitted right-turn operation, adding a subphase to the permitted phase in which right-turns are prohibited. Unfortunately, the prohibited subphase would reduce the capacity of right-turn movements when it prohibits right turns even if there are few pedestrians and bicycles crossing the street. This paper aims at quantifying the impact of both non-vehicular flows and the prohibited subphase on the right-turn capacity, and then proposes a strategy to determine appropriate prohibited–permitted right-turn operation that minimizes the capacity reduction caused by the prohibited subphase. To achieve this goal, we improved the pedestrian and bicycle adjustment factor described in the Highway Capacity Manual by taking into account: (1) the variety in space competition between pedestrians and bicycles, and (2) the effect of two conflict zones in each phase on right-turn operation. In addition, we revised the capacity estimation model in the Highway Capacity Manual, and developed a model based on bicycle/pedestrian volume fluctuation to describe the capacity reduction due to both non-vehicular flows and the prohibited subphase. Furthermore, we proposed a timing strategy for the onset and duration of appropriate prohibited subphase. When bicycle and pedestrian volumes are low, the actuated strategy turns to the permitted phase. When these volumes are moderate, the strategy turns to the prohibited–permitted operation. With the volumes increasing, the prohibited subphase onset advances and duration increases. In these two scenarios, the new strategy has higher right-turn capacity than the current pretimed prohibited–permitted operation. Unfortunately, when bicycle and pedestrian volumes are high, the strategy yields similar right-turn capacity. However, the new prohibited subphase has less potential vehicle–bicycle and vehicle–pedestrian conflicts.     

Lane-harmonised passenger car equivalents for heterogeneous expressway traffic

In order to account for variations in traffic composition during traffic analysis, passenger car equivalent (PCE) factors are used to convert flow rates of various vehicle classes into flow rates in terms of passenger car units (PCUs). Earlier studies have developed various methods to estimate PCE values but only a few of them are based on uninterrupted traffic flow, particularly for flow regimes with heterogeneous traffic where differential (lower) speed limits are imposed on commercial vehicles. This paper proposes a lane-harmonisation approach, which leverages on the high variation in traffic composition across the lanes, to estimate PCE factors for urban expressways. Multiple linear regression is used and the PCE factors obtained for motorcycles, light goods vehicles, and heavy goods vehicles are 0.65, 1.53, and 2.75, respectively. The estimated capacity flow rate after the application of the obtained PCE factors is around 2200 PCUs per hour per lane.     

基于分级多目标决策的干线公交速度引导模型

为解决干线公交速度引导存在多要素关联约束强，全局效果差的问题，本文提出基于分级多目标决策的干线公交速度引导模型。基于公交线路运行特性的全局优化指标优势分析，设计以公交线路综合准点率为主，交叉口停车次数和分段引导速度均衡为辅的线路全局优化目标体系，并考虑多目标间的关联约束和优先控制差异，构建基于拉格朗日乘子法和遗传算法分层组合的干线公交速度引导分级多目标递阶决策模型；最后，通过实际场景测试，验证模型的有效性。测试结果表明：模型能够克服非全局指标优化的局部最优问题，将全线路各班次综合准点率和交叉口停车次数由非全局指标的69.67%和2.37次 ⋅ 班-1 提升到90.53%和1.23次 ⋅ 班-1；并且综合准点率比全局多目标加权方法提升8.65%，能够较好保障综合准点率目标的优先性，有效提升干线公交的通行效率和服务可靠性。     

ISO与ITTC方法在实船航速修正应用对比

介绍了ISO15016：2015和ITTC2017两种实船航速修正方法，对比了两种修正方法的测速要求和修正流程。并通过8种具有代表性的船舶试航数据，采用两种方法对试航数据进行修正，分析了不同环境因素的修正结果，可为今后船舶EEDI测速试验和航速修正提供参考。     

高速公路相机自动标定及道路坐标系构建

为解决高速公路场景下利用视频监控系统正确描述车辆相对于道路的空间位置问题，通过引入Frenet坐标系概念，提出一种基于相机自动标定的道路坐标系模型。在相机自动标定阶段，利用线分段拟合方法从曲线车辆轨迹中提取平行于直线路段的轨迹点，并通过级联霍夫变换精确估计道路方向的消失点。然后,根据多车辆三维模型约束，对相机参数进行迭代优化。基于标定结果，将车辆轨迹映射到世界坐标系平面上，并用3次样条插值进行拟合。根据大量运动车辆在道路平面内形成的轨迹域分布特征，综合边界约束估计道路中心点。最后，结合道路中心线在各点处的法线向量与车道宽度信息确定平移量，并利用点平移运动拟合车道线，实现道路坐标系的自动建立。使用真实高速公路视频数据，在多种道路条件下进行试验。研究结果表明:在标定阶段，构建方法对不同高速公路场景的最大标定误差不超过11.55%;与最新的方法相比，直线道路平均标定误差分别降低6.68%和3.58%，弯曲道路平均标定误差分别降低7.43%和2.61%;在道路坐标系构建阶段，构建方法的平均投影距离为0.077 m，接近最新方法的0.069 5 m；而其平均精度为0.916，显著优于最新方法的0.663；所提道路坐标系能够自适应道路形态的变化，有效解决了从监控视频中描述车辆与道路之间相对位置关系的问题。     

列车撞击作用下盾构隧道管片接头错动和张开分析

建立盾构隧道三维数值模型,在管片内侧施加特定速度和角度的列车脱轨撞击荷载,获取与被撞击块相连6颗螺栓所在位置的接头错动及张开量时程曲线。通过对比分析在撞击过程中不同位置接头的错动和张开量变化趋势以及出现的最大张开、错动量,揭示在列车小角度撞击作用下盾构隧道管片接头张开和错动特性。结果表明:在速度200 km/h列车斜向12.5°撞击作用下,各螺栓位置的管片接头均出现不同程度的张开和错动,在撞击过程中各位置接头出现的最大错动量均远远超过实际工程中的限值;相对于管片接头的错动,撞击作用所造成的各位置接头平均张开量相对较小,某些位置接头在整个撞击过程中始终未发生张开。研究所得结论对盾构隧道的结构防撞和防水设计具有一定的参考价值。     

Evaluating the effects of speed reduce for shipping costs and CO2 emission

Global greenhouse gas emissions have driven up carbon dioxide levels beyond 400 parts per million, thereby increasing the rate of global warming. This paper conducted a thorough assessment of available operating strategies to identify the approach to speed reduction that is best able to minimize costs and reduce the impact of shipping on the environment. Our results indicate that optimum speed reduction is a dynamic process depending largely on charter rates and fuel prices. The significant cost advantages afforded by this approach could improve the competitiveness of ship operators.     

智能车经济性起步车速规划研究

智能车的车速决策影响燃油经济性。以起步阶段加速工况的燃油经济性为优化目标,建立了瞬态燃油消耗模型,并提出了基于该模型的经济性换挡规律制定方法;根据车辆纵向动力学方程,建立了基于前向欧拉离散方法的车速状态转移方程,以及确定相应的初末约束条件、边界条件;基于动态规划最优性原理,提出了智能车起步过程的经济性车速规划方法,建立了基于速度状态搜索策略;根据Matlab/Simulink和CarSim联合仿真,对比了典型驾驶员速度跟随模式的燃油消耗水平,结果表明,基于动态规划优化后的经济性车速及相应的挡位序列具有良好的节油特性,可为智能车经济驾驶的车速规划及挡位规划提供指导。     

车道偏离预警算法研究

为提高车辆行驶的主动安全性,文章根据车辆偏离速度将TLC算法和FOD算法相结合,针对车道偏离预警系统提出了多模式车道偏离预警算法,并搭建Simulink模型,结合Carsim进行联合仿真实验。仿真结果表明,提出的算法能更好的进行车道偏离预警。