孟加拉国典型铁路路基结构及关键控制指标研究

依托孟加拉国在建铁路项目,系统分析了该地区典型的铁路路基结构型式,对填料要求及关键控制指标进行了研究,将其控制标准与国内规范标准进行对比,并对当地常用地材进行试验研究.初步总结出了适应当地条件的经济性、应用性关键控制参数并提出了工程建议.     

中国铁路填料分类和AASHTO填料分类对比分析

近年,我国高速铁路阔步走向世界,但由于各国使用的规范差异,给海外项目设计带来困难,结合委内瑞拉北部铁路路基设计体会,对中国铁路填料分类[1]和美国AASHTO[2]填料分类标准做了简要的分类对比分析,希望对使用欧美标准的海外铁路项目路基设计起到一定的参考作用。     

中欧普速铁路路基设计主要技术标准对比分析

为了提高中国工程师对欧洲普速铁路路基设计规范体系的理解和掌握,分析对比了中欧普速铁路路基设计主要技术标准,收集分析总结中欧普速铁路路基设计规范体系,并就列车荷载、路基结构、填料和压实度进行对比。对比分析表明:中国与欧洲（英、法、德）铁路路基设计标准在设计理念上相通,路基工程应按土工结构物进行设计;列车荷载中欧规范基本相同;路基结构分层中欧规范略有差异;基床厚度中德规范最接近,英法规范取值比中国规范小;中国规范常用瑞典圆弧法,欧洲规范常用简化Bishop法、Janbu法等。     

东北铁路施工机械选型探索

针对东北铁路施工环境和机械选型的基本原则,通过对比类似机型,分别分析了铁路路基施工、隧道施工、桥梁施工、铺轨施工中典型设备选用的依据和方案,得出了适合当地施工条件的成套施工设备选用方案,为其他地区类铁路项目的机械设备选型提供参考。     

阳平水电站蓄水对宝成铁路路基稳定性的影响

目前许多水电项目旁边多为既有铁路，水电站的建设必将影响铁路安全运营，通过对嘉陵江阳平水电站工程进行现场调查，地质勘察，按照不同类型进行归类。采用数值方法分析宝成铁路在修建水电站前后的稳定性，确定了水电站蓄水对宝成铁路路基影响程度，指导水电站库区铁路路基加固防护。     

在新验标条件下土工试验有关问题的探讨

新的《铁路路基工程施工质量验收标准》对路基施工质量控制提出了更高的要求,与之相应的土工试验项目和方法也产生了一些变化。对填料的分类、分组及试验项目以及质量控制标准进行了阐述,并对土工试验中一些新的问题进行了探讨。     

新建铁路对既有铁路路基安全稳定性影响研究

基于分层总和法和GeoStudio数值软件,从沉降、水平位移和路基边坡稳定性等方面分析某新建铁路路基对既有铁路路基安全稳定性的影响。研究结果表明:分层总和法计算得出路基填筑扩建后,既有路基左线中心处沉降为6.4 mm,沉降量大于规范值;数值建模计算得到既有路基左线中心处沉降为8.5 mm,沉降量与分层总和法计算结果较为一致,均不满足轨道线路静态几何尺寸容许偏差管理值的要求;水平位移小于1.0 mm,满足规范允许值;新建路基对既有路基边坡的稳定性不造成影响,不会造成既有路基的失稳。     

铁路路基排水设施降雨重现期的确定研究

在分析研究现行规范规定的铁路路基、国家的公路排水设施降雨重现期或洪水频率基础上,设施的降雨重现期,并进行了计算分析。公路与城市道路、涵洞及小型排水构造物及不同结合目前铁路的发展要求,提出了铁路路基排水     

从常见路基病害分析基建施工存在问题

十多年来,修建铁路,在短期利益的驱动下,许多铁路路基基建施工项目质量达不到规范要求。铁路开通运营几年后,许多因质量隐患而产生的病害陆续暴露出来,影响正常的运输秩序,危及旅客及国家财产的安全。笔者管内Ⅱ级铁路正线长度近358km,多为山区铁路,路基换算长度约710km,防护及加固设备繁多。铁路运营8年以来,许多基建项目遗留的质量问题,经不起时间和雨水的考验,陆续发生病害,发生多起危及行车安全的事故。这些事故,除雨水有一定的诱因外,路基工程施工质量问题仍是主要因素。下面就基建施工中     

铁路路基工程设计标准及规范修订情况简介

铁路路基是铁路工程的重要组成部分,是承受轨道和列车荷载的基础.路基作为土工结构工程必须具有坚固、稳定、耐久性以能抵抗各种自然因素的影响,保证铁路运输的安全和畅通.随着我国铁路客货运量的不断增长,列车运营速度的不断提高,再加上对路基工程重要性认识的不断提高,路基工程主要技术标准的规定即路基工程设计规范也有多次变更,现将铁路路基设计规范演变情况简介如下.     

Railway vehicle performance optimisation using virtual homologation

Unlike regular automotive vehicles, which are designed to travel in different types of roads, railway vehicles travel mostly in the same route during their life cycle. To accept the operation of a railway vehicle in a particular network, a homologation process is required according to local standard regulations. In Europe, the standards EN 14363 and UIC 518, which are used for railway vehicle acceptance, require on-track tests and/or numerical simulations. An important advantage of using virtual homologation is the reduction of the high costs associated with on-track tests by studying the railway vehicle performance in different operation conditions. This work proposes a methodology for the improvement of railway vehicle design with the objective of its operation in selected railway tracks by using optimisation. The analyses required for the vehicle improvement are performed under control of the optimisation method global and local optimisation using direct search. To quantify the performance of the vehicle, a new objective function is proposed, which includes: a Dynamic Performance Index, defined as a weighted sum of the indices obtained from the virtual homologation process; the non-compensated acceleration, which is related to the operational velocity; and a penalty associated with cases where the vehicle presents an unacceptable dynamic behaviour according to the standards. Thus, the optimisation process intends not only to improve the quality of the vehicle in terms of running safety and ride quality, but also to increase the vehicle availability via the reduction of the time for a journey while ensuring its operational acceptance under the standards. The design variables include the suspension characteristics and the operational velocity of the vehicle, which are allowed to vary in an acceptable range of variation. The results of the optimisation lead to a global minimum of the objective function in which the suspensions characteristics of the vehicle are optimal for the track, the maximum operational velocity is increased while the safety and ride quality measures of the vehicle, as defined by homologation standards, are either maintained in acceptable values or improved.     

About Multi-Hertzian-Contact Hypothesis and Equivalent Conicity in the Case of S1002 and UIC60 Analytical Wheel/Rail Profiles

In a previous paper [1], a new method using 'multi-Hertzian' elasticity for identifying equivalent parameters of railway wheelsets rolling on defined tracks was presented. Another method also using Hertzian elasticity [2] has produced different results. Without knowing the origin of these discrepancies, the question was asked whether any of these methods could adequately describe actual non-Hertzian contacts. This paper, using as a basis Kalker's 'Contact' software which solves the non-Hertzian case for normal and tangential forces, answers this question, demonstrating that the assumption of summing Hertzian contacts is realistic provided that enough ellipses are considered. On this basis, the 'equivalent conicity' of the standard wheelset equipped with S1002 profiles rolling on UIC60 (1/40) rails is analysed in the range of small lateral displacements: around 2 mm it amounts to between 0.13 and 0.16. It is demonstrated that, due to actual wheel and rail elasticity, linearization of rigid profiles conicity, whatever method being used, is not realistic in practice.     

中—尼—印跨喜马拉雅铁路通道探讨

中国和印度两国的经济目前正处于高速发展期,双边贸易和人员交流也逐年迅速增加。一方面,虽然两国接壤,但是客运和货运主要依靠航空和海运,难以满足未来运输需求及可持续发展的要求;另一方面,邻国尼泊尔迫切需要1条连通外界的通道,以发展本国经济。本文利用引力模型预测了2050年之前中国与印度的双边贸易额,并根据历年货运量与贸易额的关系、旅客人数及人均GDP的关系及相应分担率,推算了中国—尼泊尔—印度铁路的货运量及客运量,从而分析了修建铁路通道的必要性;根据可能的铁路线路,通过工程类比估计了铁路的建设成本和回报期;最后,分析了铁路建设带来的经济效益、社会效益和环境效益。     

新建200 km/h客货共线铁路大跨度连续刚构桥设计研究

遂渝铁路是我国第一条新建时速200 km铁路,跨越涪江和嘉陵江时采用大跨度预应力混凝土连续刚构桥。在已建成的铁路桥梁中,无论是设计行车速度、大跨桥上无缝线路设计,还是结构形式均有新的突破。介绍其结构设计,并着重对其关键技术分析进行论述。     

中国铁路、隧道与地下空间发展概况

通过总结目前中国隧道的修建概况,说明中国是目前世界上隧道和地下工程数量最多、发展速度最快、地质及结构形式最复杂的国家;从时速250～350 km高速铁路、时速200～250 km既有线提速、高原冻土铁路、铁路重载运输4个方面的建设成就和4个技术平台的搭建阐述铁路快速、高效发展的现实;介绍中国中长期铁路网规划、国际铁路通道提议及将要实施的重大工程;扼要总结中国隧道及地下工程修建的主要技术：1）江、河、海底隧道修建技术;2）钻爆法施工技术;3）浅埋、超浅埋暗挖法施工技术;4）开敞式TBM全断面掘进机施工技术;5）盾构法施工技术;6）沉管法施工技术;7）辅助工法;8）明挖法地下深基坑围护结构施工技术;9）地铁车站施工技术;10）环境保护施工技术;11）高新技术改造、提高隧道施工质量技术。     

The Stationary Motion of a One-Axle Vehicle Along a Circular Curve with Real Rail and Wheel Profiles

In this paper, we present a theory on the stationary motion of a one-axle railway vehicle along a circular curve in the presence of single- or double-point contact. The rail and the wheel profiles may be either stylized or real and as an example we take the profile combination UIC60 1:40 S1002. The mathematical model of the system is based on De Pater's first-order theory [1]. The geometrical contact problem between wheel and rail is solved by using a modified Newton-Raphson procedure. Both the cases with and without friction are considered. When friction is present, the non-linear Kalker creep law [6, 7] is used to describe the physical contact. For various values of the friction coefficient, the cant angle and the curvature of the track, the contact forces are presented as functions of the velocity parameter C v = V 2 / V 2 eq , where V is the velocity of the vehicle and V eq is the equilibrium velocity of the frictionless case. For the case of stylized profiles in which both the wheel treads and the wheel flanges are conical, and the rail cross sections are circular, we have determined the velocity range with single point contact in dependence on the friction coefficient, the conicity of the tread, the curvature of the track and the cant angle.     

中国高速铁路隧道的发展及规划

介绍了中国高速铁路的发展历程,论述了隧道工程在中国高速铁路发展中的关键性作用,总结了中国高速铁路隧道的主要特点:分布区域广且地质环境复杂;隧道断面净空有效面积大;采用复合式衬砌与明洞式钢筋混凝土结构相结合的支护方式;道床形式主要为无砟轨道。对运营、在建和规划中的中国高速铁路隧道进行了系统介绍,提出中国高速铁路隧道的发展方向:形成更加完善的技术体系;优化隧道断面尺寸和设计参数;全面实施大型机械化配套施工;提高隧道建设信息化管理水平。