浮置板轨道对轨道交通箱形梁的减振效果分析

为研究浮置板轨道对轨道交通桥梁的减振效果,以32 m的轨道交通双线箱形梁为研究对象,基于联合仿真方法建立了车辆-轨道-桥梁耦合振动分析模型,计算列车荷载作用下轨道交通箱形梁的振动响应,分析了浮置板轨道对箱型梁的减振效果。结果表明,箱形梁桥上采用浮置板轨道会急剧增大钢轨和浮置板自身的振动响应;采用浮置板轨道可以降低桥梁中、高频的振动,但是会放大桥梁低频的振动响应;如需采用浮置板轨道以减少轨道交通辐射的噪声,还应考虑设置浮置板轨道后钢轨辐射噪声的增加。     

橡胶垫铺设方式对轨道板减振效果影响分析

结合隔离式橡胶浮置板轨道的减振原理,分别对不同类型橡胶浮置板轨道工作刚度进行计算分析,得出点支撑橡胶垫隔振效果最佳。建立轨道叠合梁模型,借助ANSYS软件计算分析,计算出点支撑减振垫布置在轨道板下部、以钢轨为中心内外50cm范围内浮置板竖向位移变化情况,从而对点支撑橡胶浮置板轨道系统的横向稳定性进行判断。     

大宽度变截面预应力混凝土桥面板预制技术

港珠澳大桥CB05标85m组合梁桥主梁采用"开口钢箱梁+预制混凝土桥面板"的钢-混凝土组合梁结构。桥面板采用纵向分块、横向整块预制,预制板宽15.8m、长3~4.15m、厚22.5~50cm,设9个剪力槽与钢箱梁组合;预制板钢筋骨架由上、下2层网片组成,纵、横向钢筋间距12.5cm,纵向钢筋为上下封闭式环形钢筋,其外露45cm作为湿接缝钢筋。根据桥面板预制特点,采用整体钢桁架底模系统作为预制台座,双层梳形模板、快易收口网作为侧模,通过专用绑扎胎架、吊具、侧模定位槽口等措施实现钢筋精确定位,施工中采用水洗凿毛、桥面板移位后再张拉等工艺,高效、优质地完成2 516块桥面板预制工作,预制的桥面板内实外美、精度达毫米级。     

重庆南纪门长江大桥主桥总体设计

重庆南纪门长江大桥为轨道专用桥,该桥主桥采用(34.5+180.5+480+215.5+94.5)m的高低塔双索面斜拉桥,半飘浮体系。主梁采用PK断面钢箱叠合梁,箱梁总宽23.6m,梁高3.3m。桥塔采用门形混凝土结构,北塔总高158m、南塔总高227m,基础为哑铃形承台接群桩基础。斜拉索采用1 860MPa高强平行钢丝,索塔锚固采用环向预应力,索梁锚固采用锚拉板。辅助墩及交接墩均采用板式桥墩。主梁采用悬拼施工,跨越南滨路及南滨国际段主梁化整为零分块拼装。为使桥位周边综合噪声满足环评标准,采取轨道设置钢弹簧浮置板减振道床+噪音敏感段设置全封闭声屏障+进出站车速控制在50km/h以内的减振降噪组合措施。     

JFE钢铁开发出高碳热轧钢板“SuperHot—F”

JFE钢铁开发出了用于机械的碳钢S35C·S45C热轧钢板“SuperHot—F（Formable）”，该产品具有出色的加工性能。虽为热轧钢板但却达到了与冷轧钢相当的板厚精度。如果板厚4mm以下时，可将厚度容许差控制在±80μm以下。     

大跨度混合梁斜拉桥CRTSⅢ型无砟轨道快速施工关键技术

为提高大跨度铁路桥梁CRTSⅢ型无砟轨道的施工工效,以(30+46+300+97+62.395) m高低混凝土塔混合梁斜拉桥——湖杭铁路富春江特大桥主桥为背景,提出了一种工效更高的CRTSⅢ型无砟轨道快速施工方案。该方案综合考虑施工过程中温度、桥面荷载对桥面线形的影响,针对类似工程CRTSⅢ型无砟轨道施工过程中CPⅢ控制点需多次测定、线形控制方式对工期影响较大的局限性,采用在每个底座板放样断面的桥面两侧埋设测钉作为线形观测点,以测点与放样点间高差为控制指标进行放样;基于防撞墙等附属设施施工前、后的桥面线形实测数据对有限元计算模型进行刚度修正,结合CRTSⅢ型无砟轨道的构造特点,采用刚度修正后的有限元模型计算施工预拱度以控制桥面线形。富春江特大桥主桥采用该CRTSⅢ型无砟轨道快速施工方案实际节省工期20 d,在保证施工质量的基础上达到了提高工效、节省工期的效果。     

浅谈先张法预应力板梁的预制与安装

结合宝应船闸大修扩容改造工程下闸首公路桥预制板梁的施工生产情况,介绍先张法预制空心板梁的预制生产安装、技术工艺流程等,指出了先张法预应力板梁从生产到安装各个流程中的技术要点和注意事项。     

贝雷片式龙门吊拼装工艺及受力计算

江六高速公路开发区一标预制板梁共1 663片;分两个预制场进行预制任务,每个预制场设一台50 t贝雷片式龙门吊、两台10 t贝雷片式龙门吊.其中50 t龙门吊负责板梁出坑及板梁装车任务,10 t龙门吊负责预制场的模板安装、拆卸及混凝土浇筑任务,主要介绍50 t贝雷片式龙门拼装的施工工艺.     

连续型浮置板的长度对轨道交通中车辆振动的影响

在对具有浮置板结构的无蹅轨道的分析基础上,建立了连续现浇型浮置板结构的力学模型,即弹性支撑的Bernoulli-Euler梁模型.通过对连续型浮置板结构不同的纵向长度尺寸布置对车辆系统的振动响应影响的分析,求得轨道交通无蹅轨道中连续型浮置板结构合理的布置方式.     

港珠澳大桥沉管隧道检修道安装工艺

检修道作为半隐蔽的混凝土结构,为保证精度可控、同时减少作业环境污染,放弃了现浇方案而采用预制、转运、现场安装的流水工艺,达成了精度控制"双保险"。检修道安装全过程测量3次,同时在精调过程中大面积使用螺栓支垫形式,将检修道整体线形偏差控制在1mm以内,为后期的排水沟、斜板及台阶安装打下了坚实的基础。文中旨在讨论检修道安装过程中如何把控精度,避免污染,并为今后小型混凝土预制构件的安装提供参考。     

钢弹簧浮置板轨道位移实测与分析

为评价钢弹簧浮置板轨道钢轨与浮置板位移的合理性，通过现场实测与动力学仿真计算，对比分析钢轨与浮置板在列车以不同速度通过时的位移变化，并且模拟了地铁正式运营后的最不利情况。研究结果表明:车速的改变对钢弹簧浮置板轨道钢轨与浮置板的垂向位移没有大的影响。列车荷载的增加及不平顺的恶化会导致轮轨之间的作用力加强，进而导致钢轨与浮置板的垂向位移增大。     

On vehicle/track impact at connection between a floating slab and ballasted track and floating slab track's effectiveness of force isolation

When a vehicle runs over the connection between a floating slab track (FST) and ballasted track, wheel/rail impact may occur because of the stiffness difference in the two kinds of track, and thus a transition sector is usually included at the connection to smoothen the stiffness change. This phenomenon is studied by numerical simulation using a time-domain model for an idealised case without such a transition to determine whether it is actually necessary. Calculation results show that the wheel/rail impact load is moderate for a light FST and increases with the vehicle speed or decreasing the natural frequency of the FST. From simulation the wheel/rail parametric excitation is observed, as a result of variation in the stiffness of the FST with the period of the single slab length. The wheel/rail load due to the parametric excitation also increases with the vehicle speed. In addition, good performance of vibration isolation can be seen for the FST in terms of the force transmitted to the infrastructure.     

Experimental and numerical investigation of the effect of rail corrugation on the behaviour of rail fastenings

This paper presents the results of a detailed investigation of the effects of rail corrugation on the dynamic behaviour of metro rail fastenings, obtained from extensive experiments conducted on site and from simulations of train–track dynamics. The results of tests conducted with a metro train operating on corrugated tracks are presented and discussed first. A three-dimensional (3D) model of the metro train and a slab track was developed using multi-body dynamics modelling and the finite element method to simulate the effect of rail corrugation on the dynamic behaviour of rail fastenings. In the model, the metro train is modelled as a multi-rigid body system, and the slab track is modelled as a discrete elastic support system consisting of two Timoshenko beams for the rails, a 3D solid finite element (FE) model for the slabs, periodic discrete viscoelastic elements for the rail fastenings that connect the rails to the slabs, and uniformly viscoelastic elements for the subgrade beneath the slabs. The proposed train–track model was used to investigate the effects of rail corrugation on the dynamic behaviour of the metro track system and fastenings. An FE model for the rail fastenings was also developed and was used to calculate the stresses in the clips, some of which rupture under the excitation of rail corrugation. The results of the field experiments and dynamics simulations provide an insight into the root causes of the fracture of the clips, and several remedies are suggested for mitigating strong vibrations and failure of metro rail fastening systems.     

多种地铁减振结构在直线和曲线段减振效果分析

为了研究多种地铁减振轨道结构在直线段和曲线段列车行驶时的减振效果,对比分析了铺设有单趾弹条扣件、梯形轨枕、橡胶隔振垫道床、钢弹簧浮置板道床4种轨道结构的断面处隧道壁的垂向振动加速度实测结果,然后将实测结果通过FFT变换以及考虑Z计权因子修正的1/3倍频方法得到其Z振级,对比分析减振轨道与普通整体道床隧道壁分频振级（Z振级）均方根的差值,结果表明:不同的轨道减振结构,不同的地段,不同的中心频率,隧道壁垂向振动加速度幅值都不同。总体上,钢弹簧浮置板道床轨道减振效果最好,橡胶隔振减振床轨道次之,然后是梯形轨枕轨道。     

减振型双块式无砟轨道合理刚度匹配研究

为研究城际铁路减振型双块式无砟轨道的合理刚度匹配,基于轮轨系统耦合动力学理论,结合我国城际铁路的运营特点,建立了城际铁路车辆-减振型双块式无砟轨道耦合动力分析模型,分析了列车在时速200 km和160 km时的轮轨动力响应。结果表明:对列车最高运行速度为200 km/h的城际客运专线,建议钢轨允许垂向位移控制在2 mm以内,减振垫的垂向位移应控制在1 mm左右;支点反力、钢轨位移受扣件刚度的影响显著,减振垫刚度是决定底座板加速度及道床板位移的决定性因素。城际铁路“在大站停”列车时速200 km、“站站停”列车最高时速160 km时,扣件合理刚度可取为42~49 kN/mm,减振垫的合理刚度可取为0.036~0.044 N/mm3。     

采用预制-现浇UHPC板的钢桥面铺装受力性能研究

为解决现有钢桥面铺装因大面积现浇超高性能混凝土(UHPC)产生收缩开裂,需密集配筋,施工现场需要大量蒸养设备等问题,提出了一种采用预制-现浇UHPC板的钢桥面铺装。通过钢-预制UHPC板界面、钢-现浇UHPC板界面和预制-现浇UHPC界面局部模型试验,揭示了采用预制-现浇UHPC板的钢桥面铺装各关键界面黏结性能;通过节段足尺模型试验与有限元分析,明确了车辆荷载下采用预制-现浇UHPC板的钢桥面铺装的荷载效应。研究结果表明：钢-预制UHPC板界面受拉和受剪破坏均发生于粘胶层与预制UHPC板结合面,法向抗拉和切向抗剪承载力可保守地取5.2 MPa和8.7 MPa;栓钉间距在150~320 mm之间时,栓钉加密对钢-现浇UHPC板界面抗剪承载力影响较小,可根据中国规范进行现浇UHPC板中栓钉承载力的计算,抗剪刚度可保守的取110.0 kN·mm^-1;界面凿毛处理和湿接缝采用蒸汽养护,可使预制-现浇UHPC接缝的抗剪强度分别提升23%和20%,预制-现浇UHPC接缝抗剪强度可保守地取2.4 MPa;在3倍车辆设计荷载作用下,UHPC板以及钢-UHPC板界面的应力均小于容许应力。提出的采用预制-现浇UHPC板的钢桥面铺装方案可行。     

Study of the post-derailment safety measures on low-speed derailment tests

Prevention of train from derailment is the most important issue for the railway system. Keeping derailed vehicle close to the track centreline is beneficial to minimise the severe consequences associated with derailments. In this paper, the post-derailment safety measures are studied based on low-speed derailment tests. Post-derailment devices can prevent deviation of the train from the rail by catching the rail, and they are mounted under the axle box. Considering the different structures of vehicles, both trailer and motor vehicles are equipped with the safety device and then separately used in low-speed derailment tests. In derailment tests, two kinds of track, namely the CRTS-I slab ballastless track and the CRTS-II bi-block sleeper ballastless track, are adopted to investigate the effect of the track types on the derailment. In addition, the derailment speed and the weight of the derailed vehicle are also taken into account in derailment tests. The test results indicate that the post-derailment movement of the vehicle includes running and bounce. Reducing the derailment speed and increasing the weight of the head of the train are helpful to reduce the possibility for derailments. For the CRTS-I slab ballastless track, the safety device can prevent trailer vehicles from deviating from the track centreline. The gearbox plays an important role in controlling the lateral displacement of motor vehicle after a derailment while the safety device contributes less to keep derailed motor vehicles on the track centreline. The lateral distance between the safety device and rails should be larger than 181.5?mm for protecting the fasteners system. And for the CRTS-II bi-block sleeper ballastless track, it helps to decrease the post-derailment distance due to the longitudinal impacts with sleepers. It can also restrict the lateral movement of derailed vehicle due to the high shoulders. The results suggest that, CRTS-II bi-block sleeper ballastless track should be widely used in derailment prone areas.     

Simulation of vertical dynamic vehicle–track interaction using a two-dimensional slab track model

The vertical dynamic interaction between a railway vehicle and a slab track is simulated in the time domain using an extended state-space vector approach in combination with a complex-valued modal superposition technique for the linear, time-invariant and two-dimensional track model. Wheel–rail contact forces, bending moments in the concrete panel and load distributions on the supporting foundation are evaluated. Two generic slab track models including one or two layers of concrete slabs are presented. The upper layer containing the discrete slab panels is described by decoupled beams of finite length, while the lower layer is a continuous beam. Both the rail and concrete layers are modelled using Rayleigh–Timoshenko beam theory. Rail receptances for the two slab track models are compared with the receptance of a traditional ballasted track. The described procedure is demonstrated by two application examples involving: (i) the periodic response due to the rail seat passing frequency as influenced by the vehicle speed and a foundation stiffness gradient and (ii) the transient response due to a local rail irregularity (dipped welded joint).     

基于光纤陀螺的有轨结构形变检测方法研究

光纤陀螺(FOG)属于高精度的光纤角速度传感器,将其应用于结构连续形变检测时,检测小车行驶轨迹的偏差易导致系统测量精度不高.文中提出一种基于FOG的有轨结构形变检测新方法,即在待测结构表面敷设一条轨道,通过测量轨道线形来反演待测结构形变,使得系统测量精度得到明显提高.将该方法用于长度为9.5m的模型桥测试,结果表明,光...     

无砟轨道覆盖道砟层保温效果研究

温度变化会对无砟轨道轨道板的受力和变形产生显著影响,为降低无砟轨道轨道板的温度效应,通过试验对轨道板上覆盖保温道砟层内部温度进行了监测,推导了道砟层的导温系数和导热系数;研究无砟轨道表面覆盖道砟层的厚度对轨道板上表面温度的影响,提出无砟轨道覆盖道砟保温层的材料选用原则.研究结果表明:道砟层的导温系数可取0.87×10-...