Seismic racking of a dual-wall subway station box embedded in soft soil strata

For dual-wall subway station structures embedded in soft ground, collision contacts take place at structure-structure and soil-structure interfaces during severe earthquakes. When seismic shear waves propagate up through the weak soil strata, the safety of such station is gauged by a shear-mode racking deformation which it must withstand. A dynamic system composed of discrete and finite elements is developed using an explicit formulation for the equations of motion. The dynamic interactions among distinct concrete and soil regions are modeled considering contact-slip interface as well as non-reflecting boundary. Plastic deformations in soil and concrete regions are incorporated too. A suite of strong tremors characterized by diverse levels of peak accelerations and velocities were respectively specified as input motions at bedrock. The responses of soil and structure were then examined by carrying out time-history solutions. The results of seismic response analyses illustrate that specifying a design earthquake with higher level of peak acceleration or velocity may not necessarily render larger racking in the structure. The racking deformation could be un-proportionately amplified under certain ground motions which exhibit sharp velocity pulses.     

地铁出行模式下的城市时空可达性研究

传统的空间可达性不能反映不同OD间可达程度的差异,为此,研究提出了在地铁出行模式下的城市时空可达性表达模型。该模型以地铁站点的服务范围作为研究的基本单元,各服务范围包含了不同种类与数量的兴趣点,模型以兴趣点的可自由活动时间作为时间约束,以可达范围作为空间约束,研究地铁两站点在时间和空间的共同约束下相对于整个区域的时空可达情况。通过对广州市地铁网的实例研究与分析,证明了该模型可以实现面向个人的可达性表达,提高了时空可达性研究的实用价值与应用水平,丰富了城市交通规划的理论依据。     

重庆地域特色下地铁站室内空间识别性的营造

文章对重庆地铁站地域性识别因素进行分析,并提出适合地域性的重庆地铁站室内空间特色,进而提出针对地域性形成的空间特色提出室内空间营造策略,为重庆地铁站空间识别性的研究提供一种新的思路。     

地铁车辆车轮多边形化形成原因分析

针对地铁车辆车轮多边形化问题,探讨分析车轮多边形化形成原因。提出车轮多边形化是由车轮滚动多周的振动所形成的这一创新观点,并分析车轮多边形化的顶点相位角、主振频率与运行速度之间的关系。以某直线电动机地铁车辆为例,基于建立的多体动力学模型,研究各速度下轮轨垂向力的主导频率,分析易产生车轮9边形化的速度及主导频率特性,指出在72～80 km/h的速度范围内,该直线电动机地铁车辆有形成车轮9边形化的可能。以72 km/h和80 km/h为例,给出此速度下的轮轨垂向力及其主导频率、前转向架直线电动机垂向振动加速度及其主振频率,结果表明两种速度下主导频率分别为39.08 Hz和43.48 Hz的振动有形成车轮9边形化的趋势。指出各速度下的相位角变化,并给出车轮9边形化的示意图。     

CFD在地铁站台空调系统设计中的应用

以典型的北京地铁建国门站为研究对象,以Navier-Stokes方程为基础,引入了广泛应用的标准的k-ε湍流模型,建立用于求解典型地下铁道站台内流场的计算流体力学模型。采用计算流体力学场模拟软件ANSYS CFX为计算工具,建立典型地铁车站的物理与数学模型,以试验测试与大量参考文献综合计算的活塞风结果为计算边界条件,模拟计算城市地铁空调系统的气流场,得出地铁站台典型断面的温度场、速度场以及候车区关键位置的空气温度与速度分布规律。     

基于云计算的城市轨道交通数据可视化方法及案例研究

针对城市轨道交通票卡数据流无法快速处理现状,基于云计算平台提出一种城市轨道交通大数据可视化分析方法。基于数据ID将城市轨道交通客流数据按时间段进行分表处理;基于客流关键字段建立索引数据集合并将必要客流数据字段放入对应的索引中;通过删除冗余、错误数据实现对数据筛选和清洗处理。利用ECharts中的JS插件对城市轨道交通客流数据进行可视化呈现。以JSP容器与Web服务器协同构建城市轨道交通数据可视化移动终端。以目标城市为例,对可视化系统进行验证。     

地铁屏蔽门安装前的设计测量实施

上海地铁一号线屏蔽门设计工程的测量共有12个站台,每个站台采用独立坐标系,用威特N3水准仪联测起算水准点,用徕卡TC2003全站仪联测起算平面点。用徕卡TC2003采集各特征点,采用不量仪器高,固定棱镜高的方法推算各特征点的高程;采用徕卡公司定做的标杆测量铁轨,利用徕卡测距仪测量多个距离进行检测。     

Prediction of smoke back-layering length under different longitudinal ventilations in the subway tunnel with metro train

Due to the small width and the large train blockage ratio in subway tunnel, the smoke back-layering will be different from that in the wider road tunnel with small vehicle blockage ratio. In the train blockage region of tunnel, the velocity of longitudinal ventilated air-flow interacting with the back-flowed smoke gas is different from that in the upstream tunnel without train blockage. Then the back-flowed smoke gas might be prevented in the train blockage region with higher ventilation velocity, otherwise it would be stopped in the upstream tunnel without train blockage but with lower ventilation velocity. They were taken into consideration separately and an equivalent fire source was introduced by dividing the dimensionless heat release rate of fire source into two parts in the cases where the smoke back-layering length is longer than metro train length. A series of full-scale numerical simulations are carried out with FDS to investigate the smoke back-layering length in subway tunnel with different train lengths and longitudinal ventilation velocities. The simulation results indicate that the influence of metro train length on the smoke back-layering is great and cannot be ignored any more. A global correlation model is proposed based on the dimensionless analysis and simulation results.     

都市漫游

在都市生活中，总有那些不同寻常甚至是历史性的片段或者是出于一时的冲动，又或者是因时势所迫，人们会偏离、打破已经建立的重复秩序，以完全意想不到的方式、以完全意想不到的方式、沿着没有预先设定的轨迹去体验他们朝夕相处的都市，重新发现他们习以为常的生活环境里鲜为人知的一面。     

地铁列车数据采集网络系统的设计与实现

针对地铁列车这个特殊的应用对象，开发了一个专门的数据采集网络系统，详细介绍了该系统的组成，工作原理及通信方式，重点放在其特别之处，并列举了该系统中的一个接口实例，介绍了其通信规范，帧的类型与格式，传输时序与控制流程等，运营结果表明该系统能稳定可靠地工作，满足设计的要求。