Contact Loss beneath Track Slab Caused by Deteriorated Cement Emulsified Asphalt Mortar: Dynamic Characteristics of Vehicle-Slab Track System and Prototype Experiment

Abstract

The contact loss beneath track slab caused by deteriorated cement emulsified asphalt mortar (CA mortar) has been one of the main diseases occurring in the CRTS- (China Railway Track System-) I Slab Track of high-speed railway in China. Based on the slab track design theory and the vehicle-track coupling vibration theory, a vehicle-track vertical coupling dynamic FEM model was established to analyze the influence of the contact loss length on the dynamic characteristics of vehicle and track subsystems at different train speeds. A prototype dynamic characteristic experimental test of CRTS-I Slab Track with CA mortar contact loss was conducted to verify the FEM model results. The train load was generated by the customized ZSS50 excitation car. The results showed that when the operation speed is less than 300 km/h, the contact loss with length smaller than 2.0 m barely affects the running smoothness ride safety of vehicle. The contact loss length effect on the dynamic characteristics of track subsystem is pronounced, especially on the track slab. Once the contact loss beneath the track slab occurs, the vibration displacement and the acceleration of the track slab increase rapidly, while it has little influence on the displacement and acceleration of the concrete roadbed.

Identification of Temperature-Induced Deformation for HSR Slab Track Using Track Geometry Measurement Data

“…It was found by Zhu and Cai [6] that the temperature difference between the top and bottom surfaces of track slab can reach over 16 • C. The temperature gradient load induced by the great temperature differential may result in the generation of pulling and curling stresses in the prefabricated concrete slabs [32] and structural defects. Typical temperature-induced slab track defects include interface debonding/delamination between CA mortar and track slab [4,7,12,18,25,26,32,39], decreased compressive strength, cracking and damage of CA mortar [9,15,16,33,35,[40][41][42], wide and narrow juncture defects [8], warping deformation of track slab [13,16,26,38], etc.…”

“…The design of HSR slab track has been improved a lot since 1970s (earlier slab track systems constructed in Germany and Japan [1,2]), which made it successful in HSR applications, especially in Japan and China where the newly built lines include a high percentage (up to 96 %) of slab track [3]. Nevertheless, some problems inevitably occur in track substructures due to the coupling effect of the trainload and environmental actions [4][5][6][7]. In particular, the HSR network covers a vast territory, and slab track is constructed all over the world at places with different weather conditions, e.g., great annual temperature difference, great daily temperature difference, and continuous high temperature [8,9].…”

“…To investigate how track slab damages initiate and how they affect vehicle-track system dynamics and track irregularities, previous studies carried out numerical simulations [3][4][5][6][7][8][10][11][12][13][14][15][16], full-scale tests [9,[17][18][19], and field tests [15,20,21]. These studies shed some light on repair works for defects, slab maintenance, and life-cycle management of slab track.…”

Investigation of Concrete Base‐Roadbed Surface Contact Variation‐Induced Vibration Characteristics of Vehicle‐Slab Track‐Subgrade System considering Fluid‐Solid Interaction

“…Liu et al [22] developed a vehicle-track vertical coupling model to study the influence of contact loss on the dynamic properties of vehicle and track subsystems at different train speeds, and the results were experimentally validated. With the same model, Shi [23] analyzed the effect of slab track defects, such as failure of fasteners, subgrade uneven settlement, and contact loss induced by deteriorated CA mortar, on dynamic performances of the slab track system.…”

Effect of cement asphalt mortar damage location on dynamic behavior of high-speed track

“…The authors of both these studies treated the rail as a continuous Euler beam, and their models considered the vertical vibration only. Liu et al 6 developed a vehicle-track vertical coupling dynamic finite element method (FEM) model to analyze the influence of the contact loss length on the dynamic characteristics of vehicle and track subsystems at different train speeds. The location of contact loss length was not discussed, and an extreme situation of wheel/rail separation and track displacement beyond limit caused by disabled CAM was also discussed.…”