双块式无砟轨道轨枕的优化设计研究

针对目前我国双块式无砟轨道轨枕在设计、生产、运输、铺设等过程中存在的一些问题进行探讨和分析，并在此基础上对双块式轨枕进行优化设计，以供我国双块式轨枕的设计作参考。     

市域铁路路基地段双块式无砟轨道结构设计

我国市域铁路的建设尚处于起步阶段,需要对160 km/h速度的市域铁路设计标准和轨道结构进行相关研究。依托北京新机场线工程实践应用,着重研究了双块式无砟轨道结构在160 km/h市域铁路路基地段的稳定性和安全性,基于极限状态法计算了多种荷载组合下的受力情况,并对道床板和底座板进行了配筋设计和裂缝检算。研究表明:①160 km/h速度条件下,路基地段轨道结构各动力响应指标均在限值范围内,车体脱轨系数和轮重减载率指标数值均较小,能够保证轨道结构的稳定性和列车行驶的安全性。②温度作用对道床板和底座板的受力影响较大,在设计荷载中占据主导因素。③道床板和底座板底部纵向弯矩均在荷载偶然组合作用下达到最大值,配筋时应以裂缝宽度为控制指标进行设计。     

干旱风沙地区高速铁路双块式轨枕设计研究

双块式轨枕作为双块式无砟轨道的重要组成部分,承受列车荷载并将荷载传递给道床板。武广、郑西高速铁路中分别采用了CRTSⅠ型、CRTSⅡ型双块式无砟轨道结构。对于兰州至乌鲁木齐第二双线,全线多处于严寒、温差大、风沙大、日照强、干旱缺水等恶劣自然气候条件下,国内外尚无类似条件下铺设双块式无砟轨道的工程实践。结合沿线气候特点易造成双块式轨枕沙埋、磨蚀等病害,提出加高承轨台、改进桁架筋布置、增加挡肩内配筋、枕内钢筋绝缘等措施,解决了气候对双块式轨枕带来的不利影响,并在全线得到推广应用。     

长枕埋入式整体道床施工技术

以上海城市轨道交通9号线和广州城市轨道交通4号线轨道工程为例,以长枕埋入式整体道床尤其是合成树脂岔枕道床为研究对象,结合工程施工实际,阐述长枕埋入式整体道床的施工技术,说明该技术科学合理,安全高效,确保施工的质量、进度,可降低工程成本.     

纵向轨枕规范化标准化制造关键技术

通过对纵向轨枕关键技术进行研究,设计制造出能保证安全、方便施工及运营,达到具有一定减振降噪要求的轨道系统,应用标准化、模块化的设计思路,采用工厂预制、现场拼装的施工工艺,并通过工程示范应用,从而达到纵向轨枕的规范化、标准化、模块化,形成新型轨道系统的设计、生产、施工、验收等系列标准,成为今后地铁建设减振降噪技术的新型产品结构系统。     

On the effect of unsupported sleepers on the dynamic behaviour of a railway track

The effect of unsupported sleepers on the dynamic behaviour of a railway track is studied based on vehicle–track dynamic interaction theory, using a model of the track as a Timoshenko beam supported on a periodic elastic foundation. Considering the vehicle's running speed and the number of unsupported sleepers, the track dynamic characteristics are investigated and verified in the time and frequency domains by experiments on a 1:5 scale model wheel–rail test rig. The results show that when hanging sleepers are present, leading to a discontinuous and irregular track support, additional wheel–rail interaction forces are generated. These forces increase as further sleepers become unsupported and as the vehicle's running speed increases. The adjacent supports experience increased dynamic forces which will lead to further deterioration of track quality and the formation of long wavelength track irregularities, which worsen the vehicles’ running stability and riding comfort. Stationary transfer functions measurements of the dynamic behaviour of the track are also presented to support the findings.     

A carbon footprint analysis of railway sleepers in the United Kingdom

This paper provides an assessment of the lifecycle Greenhouse Gas (GHG) emissions associated with the four most common sleeper (railroad tie or cross-tie in North America) types present in the UK rail network. It estimates the embodied material, process and transport emissions linked with the lifecycle activities of construction, relay/renewal and end-of-life of these variants at low and high traffic tonnage. The analysis suggests that at low traffic loads, the softwood sleepers perform the best over the whole simulated-period. At high traffic loads, the concrete sleepers outperform all other variants in terms of lifecycle CO₂e emissions, followed by hardwood, softwood and steel. Regardless of the scenario examined, the steel sleepers perform the worst due to the carbon intensive nature of their manufacturing process. This performance gap is amplified at high traffic loads, as their service life is excessively compromised. The analysis reveals that the end-of-life pathway of timber is a critical determinant of its footprint. Results suggest that the impact of disposing of these sleepers results in their footprint being magnified. Nevertheless, if a minimum of 50% follows the combustion pathway with subsequent heat recuperation, then a GHG reduction potential of between 11% and 18% of their footprint is feasible. From a whole-lifecycle cost lens, for higher tonnage routes, the choice of concrete sleepers results in considerable financial savings. If the infrastructure manager was to install sleepers with stiff under sleeper pads (USPs), it may achieve additional economic and GHG savings, with potential for increasing the latter using recycled carbon-neutral USPs.     

时速160 km城市轨道交通双块式轨枕设计

为研究城市轨道交通有挡肩双块轨道结构的稳定性,依托国内首条时速160 km城市轨道交通线路-北京轨道交通新机场线,对有挡肩双块式轨枕进行尺寸设计及配筋设计:(1)结合线路特点,对有挡肩双块式轨枕承轨台抗压能力及挡肩抗剪能力进行检算;(2)为计算桁架钢筋受力情况,通过有限元模型计算起吊、堆载、施工上人3种工况下双块式轨枕的受力情况。计算结果表明,起吊及施工上人荷载对双块式轨枕的受力性能影响不大;堆载对其受力性能有较大的影响,双块式轨枕的堆放层数不应大于6层。     

北京新机场线高架地段双块式无砟轨道结构设计

北京新机场线是我国首条最高速度达160 km/h的地铁线,轨道结构采用双块式无砟轨道,高架地段首次采用取消底座结构设计,为了保证轨道结构的安全可靠,有必要对无砟轨道道床结构进行结构选型及配筋设计。通过建立高架地段无砟轨道结构的有限元模型,对道床板板长、板宽、板厚进行了选型分析。针对无砟轨道无底座设计方案,考虑了列车荷载、温度梯度、桥梁挠曲3种主要荷载类型,提出了荷载组合方案,研究其关键控制因素,对道床板进行了配筋设计及检算。通过参数比选,完成了道床板的尺寸参数选择;在3种荷载类型中,温度梯度在道床板中引起的弯矩值最大,在设计荷载中占据主导因素,合理减小道床截面高度可有效降低温度梯度作用;道床板配筋应以控制裂缝为原则进行设计。     

客运专线双块式无碴轨道施工工艺与造价分析

介绍一种新型无碴轨道形式即双块式无碴轨道的施工工艺过程，并进行造价分析。此文对现有几种轨道形式进行比较分析。指出双块式无碴轨道是一种适合我国复杂地形的客运专线轨道形式。