Papers by Keyword: Ballastless Track

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Authors: Yuan Xing Hao, Feng Dai, Rong Shan Yang
Abstract: To figure out the structure and influencing factors of welded welded turnout slab convex block of ballastless track on bridge, according to the characteristics of force and displacement of welded turnout on bridge, the turnout-bridge-platform integration computation model was established by finite element method. Taking the ballastless turnout on a continuous beam bridge as the example, the longitudinal force and displacement of the bridge and parts of the turnout was obtained by the means of changing the numbers of slab, the stiffness of convex block support and the temperature range of slabs. The calculation results indicate: using three slabs is reasonable for the ballastless turnout on bridge; The stiffness of convex block supports on slabs should be set between 250kN/mm and 300kN/mm; Since the change of longitudinal force is very large, while the other parameters change little, with the change of the temperature range of slabs, slabs in turnout should be strengthen.
1664
Authors: Yue Lei Qian, Xin Ming Li
Abstract: In the process of building the ballastless track of the high speed railway from Wuhan to Guangzhou, the measuring method of the CPⅢ control network has played an extremely critical role. In this article, the form layout, measuring method, precision requirements and some other contents of the high speed railway ballastless track CP Ⅲ have been proposed. It has been proved that this control network has reliable technology basis and meets the construction requirements, which is available for other similar engineering.
1817
Authors: Jia Yuan Tao, Yu De Xu
Abstract: To solve the problem that there is vertical track profile irregularity with long wavelength and large amplitude a method of adjustment based on cubic spline interpolation was proposed in this paper. The key step of the method is to set up reference sleepers. This paper made an adjustment scheme for a 500-meter-long ballastless track section as an application case. An evaluation for the scheme was done by considering the evaluation indexes of regularity indexes, rail curvature and vehicle-track system dynamic responses. The evaluation result indicates that the method based on cubic spline interpolation is effective on track profile irregularity adjustment.
613
Authors: Wang Fang, Bing Han, Shao Kun Yang
Abstract: Creep will lead to increasing deflection of prestressed concrete girder, which may induce rails uneven, especially to ballastless tracks in high-speed railways. In this paper, two creep models, CEB-FIP90 and ACI209, were used in a finite element model to analyze influences of creep on simply supported prestressed concrete box girders which are used in high-speed railway in China. Sensitivity analysis was carried on towards curing age, secondary dead load, loading time and prestressing method on deformation of the girder. The results show creep should be controlled in engineering to ensure driving security.
733
Authors: Lin Ya Liu, Jin Wang, Rui Lv
Abstract: By using the finite element analysis software ANSYS, a three-dimensional dynamic finite element model of ballastless track rail –floating slab was established. The model takes into account of the track irregularity case, the analysis the dynamic response characteristics of the rail and floating slab under the vertical force in the track structure. The results showed that: when the train load goes through the line, the dynamic response of the rails and floating slabs gradually increases to maximum and then decreases; the maximum response displacement of rail is at 0.625mm ~ 0.75mm and the maximum response acceleration values is in between 5000m/s2~6000 m/s2; the maximum response displacement value of floating slab is about 0.25mm, the maximum response acceleration value is between 0.8 m/s2~1.2m/s2.
3907
Authors: Jian An Cao, Mei Xin Ye, Wen Qi Hou
Abstract: Aiming to Ronggui Bridge (RGB) on Guangzhou-Zhuhai Intercity Rapid Rail Transit (GZIRRT), long term deformation control of long-span pre-stressed concrete continuous rigid frame bridge with ballastless track was studied. Comparing with the non-controlled deformation, extend track laying six months later after bridge construction, reserve 48 post-tensioned cables in middle spans and tension 12 external tendons after tracking laying were all effective in decreasing the long term deformation of RGB with individual application. Taking bridge construction and railway service in consideration, applying the foregoing three measures in combination, deformation of RGB 20 years later after track laying was effectively controlled within 12.8mm in the side spans and 21.9mm in the middle spans, which is less than the deformation limitation of bridges with ballastless track. The combined measure has been adopted in the actual construction of RGB.
1515
Authors: Gao Liang, Ke Ming Yin, Yin Hui
Abstract: In this paper, based on the elastic foundation beam theory, the influence rules of every combination of loads and operating modes for ballastless track of Linear Induction Motor (LIM) track traffic are studied. In addition, according to the construction character of prefabrication and cast-in-situ, the rules of how construction influences the mechanical characteristics of the ballastless track structure are given. On the basis of synthetical analysis of the distribution rules of ballastless track’s internal force, some appropriate suggestions for design and construction are put forward.
725
Authors: Yong Zhi Min, Jian Wu Dang, Zhen Hai Zhang
Abstract: In order to achieve the online surface settlement monitoring of ballastless track,an online surface settlement monitoring system with difference image type has been established, of which the components, the preprocessing measures of images, the precise positioning methods of laser spot have also been researched. The device mainly contains a dot laser and a point-position measurement device that uses a CCD to detect the position change of the laser spot image. Any position change of the dot laser can be measured and the settlement for one point can be obtained remotely. The multi-point settlements can be obtained by using a series of such devices. Some methods such as automatic background sub-tractions and high-precision method for locating the centers of laser spots have been adopted to enhance the stability, adaptability and accuracy of the measurement system. The device has been used in some railway sites and it has the advantages of high accuracy, low-cost and easy installation.
259
Authors: Jian Qiang Cheng, Xiao Hui Zeng, Yan Ke Yang, Hai Peng Gu
Abstract: In this paper,the functions and performances of filling layer of self-compacting concrete(SCC) in CRTS(China Railway Track System)-Ⅲ type track system were introduced. Developments of SCC including design methods and test method was described in detail. The influencing factors of workability of SCC was analysised. The trends of future development of mix proportion design methods,durability evaluation admixtures,applications were discussed.This paper also pointed that it's importance for SCC to studying the quality control methods and the application.
438
Authors: Xiang Min Li, Suo Yan Zhang, Jun Liu
Abstract: At present ballastless track has been widely applied to railway line for passenger in our country, therefore it has broad prospect. Cracks in ballastless track slabs are inevitable in the construction and operation of high-speed railway. Based on comprehensive investigation of documents, and taking cracks in ballastless track slabs as the main object, systematic and deep research has been done within this paper. The main research contents are as follows: First of all, the structure characteristics of CRTSIII ballastless track in high-speed railway are briefly introduced; Secondly, the paper mostly introduces the impacts what cracks make, the characteristics of cracks and how they form. Subsequently the paper introduces what are made to prevent cracks.
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