BIM技术在轨道梁线形控制领域的应用研究

为提高跨坐式单轨轨道梁的线形控制精度,在总结跨坐式单轨交通技术特点的基础上,结合轨道梁的区间设计资料建立动态数据库,对区间轨道梁的线形控制技术进行深入研究,提出集轨道梁工法计算、可视化查看、模拟架设为一体的BIM解决方案。并基于MicroStation平台,编制跨坐式轨道交通PC轨道梁三维工法设计软件,初步实现了轨道梁从设计到施工的一体化流程,使轨道梁线形控制精度达到毫米级。     

专家故障诊断系统在97型25Hz相敏轨道电路故障诊断中的应用

使用专家故障诊断系统对97型25Hz相敏轨道电路故障红光带问题进行监测;通过案例法详细描述实现过程,包括专家故障诊断系统的构成,提取专家经验形成知识库,以及使用推理机进行推理运算,得出相关结果等。     

2018版铁路轨道施工质量验收标准解读

介绍《高速铁路轨道工程施工质量验收标准》(TB10754-2018)和《铁路轨道工程施工质量验收标准》(TB10413-2018)的编制背景、前期调研情况和修编原则,重点阐述CRTSIII型板式无砟轨道、无缝线路等主要修编内容,对隐蔽工程影像留存提出建议,便于项目参建各方全面掌握验收标准的主要内容和贯彻执行验收标准。     

Data-driven optimization of railway maintenance for track geometry

Railway big data technologies are transforming the existing track inspection and maintenance policy deployed for railroads in North America. This paper develops a data-driven condition-based policy for the inspection and maintenance of track geometry. Both preventive maintenance and spot corrective maintenance are taken into account in the investigation of a 33-month inspection dataset that contains a variety of geometry measurements for every foot of track. First, this study separates the data based on the time interval of the inspection run, calculates the aggregate track quality index (TQI) for each track section, and predicts the track spot geo-defect occurrence probability using random forests. Then, a Markov chain is built to model aggregated track deterioration, and the spot geo-defects are modeled by a Bernoulli process. Finally, a Markov decision process (MDP) is developed for track maintenance decision making, and it is optimized by using a value iteration algorithm. Compared with the existing maintenance policy using Markov chain Monte Carlo (MCMC) simulation, the maintenance policy developed in this paper results in an approximately 10% savings in the total maintenance costs for every 1 mile of track.     

境外港口升级改造工程建设要点

随着亚非拉国家腹地经济的发展,升级改造类工程项目逐渐增多。结合案例,分析码头升级改造工程的制约因素及需要重点考虑的问题;对港口规划中码头规模确定、码头前沿线确定所需考虑的主要因素及滚装码头的布置形式,码头结构设计中结构稳定性、整体性所需考虑的要素及解决方案,以及施工过程中所需考虑的主要问题等进行系统的对比分析。     

A connected-vehicle-based dynamic control model for managing the bus bunching problem with capacity constraints

This paper describes a connected-vehicle-based system architecture which can provide more precise and comprehensive information on bus movements and passenger status. Then a dynamic control method is proposed using connected vehicle data. Traditionally, the bus bunching problem has been formulated into one of two types of optimization problem. The first uses total passenger time cost as the objective function and capacity, safe headway, and other factors as constraints. Due to the large number of scenarios considered, this type of framework is inefficient for real-time implementation. The other type uses headway adherence as the objective and applies a feedback control framework to minimize headway variations. Due to the simplicity in the formulation and solution algorithms, the headway-based models are more suitable for real-time transit operations. However, the headway-based feedback control framework proposed in the literature still assumes homogeneous conditions at all bus stations, and does not consider restricting passenger loads within the capacity constraints. In this paper, a dynamic control framework is proposed to improve not only headway adherence but also maintain the stability of passenger load within bus capacity in both homogenous and heterogeneous situations at bus stations. The study provides the stability conditions for optimal control with heterogeneous bus conditions and derives optimal control strategies to minimize passenger transit cost while maintaining vehicle loading within capacity constraints. The proposed model is validated with a numerical analysis and case study based on field data collected in Chengdu, China. The results show that the proposed model performs well on high-demand bus routes.     

城市高架桥宽幅预应力盖梁优化设计分析

以城市小箱梁高架桥的宽幅预应力盖梁为对象,对三种不同类型的桥墩盖梁进行设计分析,提出多个优化改进措施,并建立对应的有限元模型,对宽幅预应力盖梁的结构构造、预应力配束、墩梁约束、梁片架设、施工阶段划分等方面进行模拟和调整,计算和分析梁片架设过程及运营期盖梁的受力性能.结果 表明,墩顶处盖梁受力复杂,计算应准确模拟梁片架设...     

基于互补滤波的轨道不平顺动态测量方法

现有高速铁路轨道动态检测主要采用基于加速度计和测距传感器数据的惯性基准法,由于加速度计具有信噪比低、积分漂移大等特点,限制了其在轨道长波不平顺和低速下的测量精度,因此提出基于互补滤波的轨道不平顺动态测量方法。首先,优化系统硬件结构,在转向架前后安装测距传感器;其次,采用轨面上"两点弦"测量模型,推导基于光纤陀螺仪数据的角速度测量法;通过测量系统传递函数的幅频特性分析,发现角速度测量法在测量30 m以内的短波不平顺时存在衰减,为此提出互补滤波方法,即对加速度测量法与角速度测量法进行融合计算;最后,用轨道-车辆动力学仿真对3种方法的精度进行实例分析。结果表明:相较于角速度测量法,互补滤波测量法有效补偿了其在测量30 m以内的短波不平顺时存在的高频衰减的不足;相较于加速度测量法,互补滤波测量法将平均精度提高了24%～80%,因而它具有噪声敏感度低、受检测速度影响小等优点。     

计及频率约束的潜艇环肋圆柱壳优化设计研究

基于多岛遗传算法,研究了环肋圆柱壳静水压力作用下,考虑强度和稳定性约束和频率约束时质量最轻的优化设计问题,讨论了强度约束和稳定性与频率约束以及材料、几何参数对优化结果的影响.环肋圆柱壳经优化后,壳板的质量比例大约是70%,肋骨质量占30%,并且随壳体的长径比(L/R)变化不大.环肋圆柱壳的优化中,肋骨的应力约束是主要约束,肋骨应力已经非常接近许用应力标准,其他应力、局部和总体失稳压力还有一定的储备.提高材料的屈服极限,可以显著降低总质量,但是肋骨也很接近许用应力标准.     

某空间螺旋塔斜拉桥合理结构体系研究

某斜拉桥方案采用反对称螺旋形桥塔,空间四索面,造型较为新颖。由于桥梁结构较为复杂,为选用适宜的结构体系,基于桥梁结构的受力形态,在综合比较了漂浮体系、半漂浮体系、半固结体系的优劣后,确定半漂浮体系为最佳方案,并进一步讨论了地震作用下该桥合理的约束体系。这一流程对解决类似复杂结构桥梁合理结构体系的问题有一定参考价值。