当前铁路隧道施工亟待解决的若干技术问题

高速铁路隧道工程建设标准高,施工难度大,安全风险高,施工管理要求严格。文章以贵广铁路隧道工程为实例,结合当前国内隧道施工技术现状和贵广铁路隧道创新技术的现场实践,研究分析了制约隧道施工安全和施工效率的突出技术问题,取得了一系列研究成果:①基于精细爆破技术的微台阶开挖工艺可有效解决IV、V级围岩隧道开挖进度与工序安全距离之间的矛盾;②得益于通风技术和空气净化技术的进步,无轨运输方式可以适应于长大隧道的施工;③隧道仰拱快速施工设备和隧道沟槽移动模架的开发应用填补了这一领域的空白;④信息化施工是未来隧道施工技术发展的大趋势。     

城市轨道交通对房地产价值的影响研究——以武汉市轨道交通为例

城市轨道交通是一种快捷、高效、节能环保的大容量城市客运交通方式,而且对于沿线房地产的开发具有巨大的带动作用.本文定性分析了城市轨道交通对房地产价值的影响机理,并采用地价影响函数模型,对武汉城市轨道交通1号线地价影响函数相关参数进行了标定.定量研究证实了城市轨道交通时房地产价值的拉动作用.最后提出了武汉市轨道交通与房地产...     

基于高速铁路软土路基固结沉降有限元分析

利用大型有限元软件ABAQUS,结合工程实例分析了软土路基分步修筑固结沉降的变形特性。计算结果表明:在路基分步填筑过程中,填土加载引起内部孔隙急剧变化,水体流失产生附加应力导致路基沉降。因此,施工中通过控制填土的速度来减小路基沉降是提高路基修筑质量的一个重要手段。同时,该标段结合实际情况,采用旋喷桩和土工栅格的加固方法,通过路基施工后沉降观测数据来看,效果明显。     

大跨度钢箱叠拱桥在高速铁路中的应用研究

新建哈尔滨-大连高速铁路跨越长春市富民大街设计采用138m钢箱叠拱,为国内首次采用的新型拱桥结构,是目前国际上同类桥梁中的跨度最大、位于严寒地区的桥梁,也是国内第一座应用实体圆钢吊杆铁路桥梁,对该桥应用中的关键技术实体圆钢吊杆的连接及低温疲劳特性、拱脚的合理构造及局部应力、对无砟轨道适应性、车桥耦合动力效应等进行了系统计算分析和试验研究,其研究成果已应用于新开河特大桥中,详细介绍桥式方案及在高速铁路应用中的关键技术研究成果。     

铁路500m长钢轨生产工艺流程及规模的探讨

针对目前铁路焊轨基地的实际,对长钢轨焊接工艺进行说明,通过工艺流程示意图,详细介绍铁路500 m长钢轨生产的工艺流程。原料为100、25 m钢轨时,分别计算日生产长钢轨能力,从而确定年生产规模。根据生产能力和实际调研,确定原料轨存轨台、长钢轨时效台、长钢轨成品台、工位规模及辊道线间距,为将来新建或改建长钢轨焊接基地提供数据参考。     

罕遇地震作用下高速铁路减隔震简支梁桥合理计算模型的探讨

以往在分析减隔震桥梁的地震响应时,由于考虑到桥墩和基础应保持弹性工作状态,在基于强度的设计中偏于安全考虑桥墩一般采用毛截面刚度建立弹性梁单元模型。实际上,在罕遇地震作用下,桥墩墩底截面虽然未达到屈服状态,仍然会出现保护层混凝土开裂,并导致桥墩刚度降低。此时,应考虑对桥墩刚度进行适当修正以估计桥梁的各项地震响应参数,这也有利于实现减隔震桥梁基于位移的抗震设计。结合西部高速铁路中典型的简支梁桥结构形式,分别采用弹塑性纤维梁柱单元、弹性梁柱单元、考虑刚度修正的弹性梁柱单元模拟桥墩建立3种计算模型,探讨适用于罕遇地震作用下的高速铁路减隔震桥梁的合理计算模型。结果表明,当罕遇地震作用下桥墩位移延性超过0.5时,考虑刚度修正的弹性梁柱单元模拟桥墩的计算模型能够较好地估计桥梁各项地震响应参数。     

Gantry crane operations to transfer containers between trains: A simulation study of a Spanish terminal

Freight transfer operations are critical in combined transport networks. In this paper a simulation model and modelling approach to the transfer of cargo between trains at rail terminals is presented. The model is used to study the Port-Bou terminal, the main intermodal terminal at the Spanish-French frontier. Four different gantry crane operation modes to interchange containers between trains are evaluated. These operation rules are tested in several scenarios to examine the critical factors of the system and the best operation rule for each situation. Latest generation software is used to develop the model that incorporates modular programming and enhanced graphic systems for output representation. It allows a dynamic display of the simulated system and, likewise, the possibility of developing modules that can be reused in other studies. The research shows how simulation can be a useful planning tool in the rail transportation context.     

高速铁路进站节能坡设计方法研究

在线路纵断面的设计中引入节能坡设计理念,对优化线路纵断面设计、降低牵引能耗值和节省运营支出具有重要意义。根据高速铁路的特点,提出高速铁路进站节能坡的设计方法和计算算法,给出计算流程,确定各影响参数的约束条件。开发进站节能坡设计程序模块,实现多参数化的进站节能坡设计。在此基础上,采用计算机仿真分析方法,对车站坡段坡度、车站中心至节能坡变坡点距离、动车组编组质量、进站制动力使用系数、节能坡进入初始速度5个主要影响因素进行计算和仿真分析,确定各因素对进站节能坡的影响程度,为进站节能坡的设计提供参考和依据。     

Vibration control in train–bridge–track systems

To study the problems associated with vibration control of train–bridge–track systems a mathematical model with the capability of representing supplementary vibrational control devices is proposed. The train system is assumed as rigid bodies supported on double-deck suspension mechanism with semi-active features. The bridge system is modeled using the modal approach. Vibration control for bridge responses is provided by tuned mass dampers. A non-classical incremental Eigen analysis is proposed to trace the system characteristics across the time. In an example, the capability of the proposed model in investigating the vibration control prospects of a bridge–train system is shown. The results indicate the effectiveness of active suspension mechanism in reducing train's body movements, particularly the pitching angle and the vertical accelerations. Accordingly, the results also verify the potential of TMD devices in reducing the bridge responses at resonance motions.     

The effect of slow zones on ridership: An analysis of the Chicago Transit Authority “El” Blue Line

Transit agencies frequently upgrade rail tracks to bring the system to a state of good repair (SGR) and to improve the speed and reliability of urban rail transit service. For safety during construction, agencies establish slow zones in which trains must reduce speed. Slow zones create delays and schedule disruptions that result in customer dissatisfaction and discontinued use of transit, either temporarily or permanently. While transit agencies are understandably concerned about the possible negative effects of slow zones, empirical research has not specifically examined the relationship between slow zones and ridership. This paper partially fills that gap. Using data collected from the Chicago Transit Authority (CTA) Customer Experience Survey, CTA Slow Zone Maps, and, the Automatic Fare Collection System (AFC), it examines whether recurring service delays due to slow zones affect transit rider behavior and if the transit loyalty programs, such as smart card systems, increase or decrease rider defections. Findings suggest that slow zones increase headway deviation which reduces ridership. Smart card customers are more sensitive to slow zones as they are more likely to stop using transit as a result of delay. The findings of this paper have two major policy implications for transit agencies: (1) loyalty card users, often the most reliable source of revenue, are most at risk for defection during construction and (2) it is critical to minimize construction disruptions and delays in the long run by maintaining state of good repair. The results of this paper can likely be used as the basis for supporting immediate funding requests to bring the system to an acceptable state of good repair as well as stimulating ideas about funding reform for transit.