Railway Track System Research Articles

Impact of metro vibrations on people: critical aspects of designing vibration mitigation interventions

A methodology for assessing and mitigating the impact of metro infrastructure generated vibration and ground-borne noise on people is described. This methodology combines techniques for analyzing vibration measurements and predictive modeling to identify effective mitigation interventions. These interventions require working on existing railway track systems and involve interruption of service, unlike noise mitigation interventions that can be implemented without interfering with rail and road infrastructure. For this reason, it is important to identify the most effective mitigation techniques to minimize the impact on the population and simplify on-site implementation. The methodology was applied in Milan metro lines where the vibration level was estimated, and a vibration mitigation system was designed. The vibration phenomenon was quantified through accelerometric measurements taken in several buildings affected by the disturbance from vibration. The measured vibration levels were compared with reference level established by standards. The maximum difference obtained from this comparison was used as input data for the design of the mitigation intervention. The vibration mitigation interventions involve increasing the total mass and elasticity of the existing system. Their effectiveness was verified through numerical calculation using parametric software confirming the required amount of mitigation.

Numerical investigation on loading pattern of railway concrete slabs

Despite the recent surge in the construction of ballastless railway tracks, there exists a notable research gap concerning the rail seat load (RSL) associated with these track types. The RSL is the load transferred from the rail to the fastening system, the plate beneath the rail and the rail pad. The prediction of RSL in ballasted track systems is widely investigated, however, there has been a relative lack of research into the ballastless railway track systems. In this paper, a 2D finite element model (2D FEM) was adopted to evaluate the RSL concerning the effective parameters, including sleeper spacing, fastening system stiffness and the flexural modulus of the rail. The numerical model was validated through a field test performed in the study. Moreover, a mathematical expression was proposed to determine the RSL ratio for concrete slab tracks. The RSL directly correlates with the sleeper spacing and the fastening stiffness, while this relation with the flexural rigidity is inverse. Based on the results, it was found that the RSL ratio obtained from the conventional methods differed considerably from the proposed mathematical expression. More specifically, this difference was observed in almost all of the values in the sleeper spacing and flexural rigidity of rail for the Kerr model except 0.68 m and 5 MN.m2, respectively.

Experimental investigation and fluid-structure interaction modelling of the casting of self-compacting concrete for CRTS III slab track in the curved segments

Ensuring the casting quality of self-compacting concrete (SCC) is crucial for the operational safety and durability of China railway track system (CRTS) III slab track. However, the mechanisms of key factors influencing flow behaviors of SCC and structural responses remain insufficiently understood, nor is the relationship between flow behaviors and structural responses during casting. In this study, fluid-structure interaction (FSI) models of SCC casting were developed and verified by full-scale physical tests, comprising slump flow, L-box flow and casting of SCC in an actual track at the field of Laixi-Rongcheng high-speed railway. Through in-depth analysis on the casting process of SCC in curved segments with a super elevation of 80 mm, the relationship between flow behaviors and structural responses was established. Furthermore, the influence mechanisms of key factors on flow behaviors and structural responses were investigated systematically. Results show that during gravity-fed SCC casting, its flow velocity diminishes, thus increasing the static pressure and the forces exerted on the slab by SCC. These vertical and lateral forces increase to 147.16 and 7.83 kN through three stages of development, acceleration and stabilization, resulting in commensurate structural responses. At the end of casting process, the central region of the slab exhibits maximum vertical deformation of 0.95 mm and tensile stress of 1.07 MPa. The tension rods at the side with lower elevation bear greater vertical and lateral forces than the ones at the side with higher elevation. The rise of funnel height from 1.05 to 1.35 m accelerates the casting process but increases the forces exerted by SCC by up to 26 % and augments the associated response of entire structures, whereas the funnel diameter shows little effect. Increasing yield stress of SCC from 9.3 to 49.3 Pa produces a more uniform flow morphology and thus higher static pressure and force by SCC in the middle region of the slab, impacting the structural responses by up to 15 %. The growth of plastic viscosity from 59 to 99 Pa⋅s significantly affects the volume rate and casting time by up to 66 % but has little effect on the flow morphology, fluid pressure and structural responses. In order to ensure high quality casting of SCC, five clamping beams are suggested with two beams positioned at either side of the slab and the other three evenly placed along the middle region of the slab.

A refined track dynamic model considering the bending properties of iron pad: Proposal and validation

Iron pads are crucial components in rail fastening systems, characterized by their load-bearing and force-transmitting capabilities. This study presents and validates a track dynamic model considering the bending properties of iron pad, offering a comprehensive analysis of their dynamic performance under train loads. The primary aim is to employ iron pads as key elements for monitoring and detecting potential defects throughout the track’s service life. Initially, the construction of the track dynamic model is outlined, followed by an in-depth explanation of how the iron pads integrate with the track model. This involves introducing an enhanced Kelvin-Voigt three-element model and elaborating on the parameter selection for the spring element using a nonlinear spring model that accounts for voids and their relevant conditions. Subsequently, a systematic comparative analysis is performed to evaluate the accuracy of simulating iron pads using solid, shell, and beam elements, along with a proposed strain correction method. Finally, the established model and methods are employed to simulate and analyze the dynamic response of iron pads under typical defect conditions. These results indicate that iron pads can effectively reflect the failure conditions of the railway track system, making them ideal sensing elements for the dynamic monitoring of track structures. The enhanced model developed in this study holds significant theoretical and practical value, contributing to the safety monitoring and defect analysis of railway operations.

Mechanical characteristics of track slab and clamps during the pouring of self-compacting concrete in the China Railway Track System III slab track

The pouring of self-compacting concrete (SCC) is crucial for ensuring the construction quality and comfort of slab tracks. In this study, a fluid–structure coupling pouring model of SCC was established based on the coupled Eulerian–Lagrangian (CEL) approach. It was applied to trace the forces and displacements of track slab and clamps during SCC pouring. The influences of some key parameters, such as the pouring equipment, technology, and rheological properties, were investigated, including the height and diameter of the funnel, pouring velocity, and plastic viscosity of the SCC. The results indicated that during pouring, the floating force and maximum vertical displacement of the track slab, as well as the vertical forces of the clamps, initially remained stable before undergoing rapid changes, eventually reaching stable values. The flow velocity of SCC in the pouring hole and its rebound primarily influenced these mechanical indicators. The funnel height positively affected the floating force of the track slab, negatively affected the vertical forces of the clamps, and slightly affected the peak values of the maximum vertical displacement of the track slab. By contrast, the funnel diameter had little influence on these mechanical behaviour indicators. As the pouring velocity increased, the floating force of the track slab and vertical forces of the clamps significantly increased. Moreover, the peak values of the maximum vertical displacement of the track slab increased to 0.47 mm at a pouring velocity of 0.03 m/s. In the case of low plastic viscosity, an increase in plastic viscosity led to a visible decline in the floating and clamp forces. However, when the plastic viscosity exceeded 80 Pa•s, further changes had little effect on the mechanical indicators owing to the combined effects of excessively low flow velocity and rebounding.

LCC-based approach for design and requirement specification for railway track system

AbstractLife cycle cost (LCC) analysis is an important tool for effective infrastructure management. It is an essential decision support methodology for selection, design, development, construction, maintenance and renewal of railway infrastructure system. Effective implementation of LCC analysis will assure cost-effective operation of railways from both investment and life-cycle perspectives. A major setback in the successful implementation of LCC analysis by infrastructure managers is the availability of relevant, reliable, and structured data. Different cost estimation methods and prediction models have been developed to deal with this challenge. However, there is a need to include condition degradation models as an integral part of LCC model to account for possible changes in the model variables. This article presents an approach for integrating degradation models with LCC model to study the impact of change in design speed on key decision criteria such as track possession time, service life of track system, and LCC. The methodology is applied to an ongoing railway investment project in Sweden to investigate and quantify the impact of design speed change from 250 to 320 km/h. The results of the studied degradation models show that the intended change in speed corresponds to correction factor values between 0.79 and 0.96. Using this correction factor to compensate for changes in design speed, the service life of ballasted track system is estimated to decrease by an average of 15%. Further, the expected value of LCC for the route under consideration will increase by 30%. The outcome of this study will be used to support the design and requirement specification of railway track system for the project under consideration.

Fatigue life prediction for CA mortar in CRTS II railway slab track subjected to combined thermal action and vehicle load by mesoscale numerical modelling

The fatigue life of the cement asphalt (CA) mortar in the slab track of the China Railway Track System (CRTS) II is crucial to the smooth and safe operation of high-speed railways. To investigate the fatigue life of the CA mortar under the combined thermal action and vehicle loads, this paper develops a new coupled thermal-mechanical finite element (FE) model for the concrete slab track at the mesoscale. First, the meteorology and heat transfer principle are adopted to simulate the temperature distribution of the concrete slab track. The heterogeneous characteristics of the concrete of the precast slab are modelled by the three-phase composite material at the mesoscale using the new developed random aggregate algorithm. Then, the energy-based exponential cohesive zone model is adopted to simulate the interface between the CA mortar and the precast concrete slab. The proposed mesoscale numerical model can provide reliable predictions for the temperature distribution and the deformation of the precast concrete slab under thermal action, which are confirmed by the relevant field measurements. Finally, the fatigue life of the CA mortar is estimated by the nonlinear damage cumulative method associated with the stress time history under the combined thermal action and vehicle load. From the obtained results for the numerical example, the thermal action can decrease severely the fatigue life of the CA mortar, and the fatigue life varies significantly at different positions, with the most vulnerable zone located near but not directly below the rails.

Quasi-distributed optical fiber sensing for the coupled vibration analysis of high-speed train-bridge coupled system under earthquakes

Due to the extensive construction of high-speed rail lines passing through seismically active areas, the possibility of a sudden earthquake occurring during train operation is very high. Additionally, the earthquake will intensify the dynamic response of trains and bridges, causing serious bridge damage. In this work, the dynamic response behavior of the bridge structures in the coupled train-bridge system under the earthquake is investigated based on the 4-table shaking table system. Shaking table experiments are also conducted on a high-speed railroad model of simple-supported girder bridge at a scale of 1/10 with the simulated layers of China Railway Track System type II (CRTS II) ballastless track slabs. The strain responses of various components, including rails, track plates, base plates, and beams, were measured on the bridge using quasi-distributed fiber optic gratings, both with and without seismic actions. Additionally, the seismic isolation characteristics of the fasteners and the CA mortar layer were investigated. The dynamic performance of the coupled train-bridge system under earthquakes was studied in both the time and frequency domains.

Damage and fracture investigation of self-compacting concrete in the filling layer of CRTS-III using three-point bending tests

Literature about filling layer self-compacting concrete (FLSCC) has indicated that FLSCC plays a crucial role in its application to Chinese railway track system III (CRTS-III). It is apparent that the damage characteristics of FLSCC have not been clearly investigated, as the actual working conditions are not considered enough. There exists a remaining gap about the mechanical properties and fracture behaviors of FLSCC under bending loads. In order to fill this gap, in this study, three-point bending (TPB) tests on the FLSCC beams with precast notches were performed based on the real bending situation of FLSCC in CRTS-III. Acoustic emission (AE), strain gauges and a digital camera were utilized to monitor the fresh evolutionary laws of micro- and macro-cracks as well as the corresponding damage morphology. The study presents that the monitored load-crack mouth opening displacement (P-CMPD) curves, load-strain (P-ε) curves and AE activity curves all exhibited similar distributions, including four stages with increasing bending loads. In term of the AE activities, the first apparent crack in the interior and warning point of failure can be detected by analyzing the captured AE activities of the FLSCC beams. In addition, the dominant failure mode of the specimens was determined as tensile cracks according to the rising angle-average frequency (RA-AF) criterion for potential FLSCC application in terms of the limiting ratios. This failure mode indicates that under pure bending loads, the mid-span section is subjected to the maximum bending moment, and the specimen experiences tensile damage. Therefore, for future practical application, the structural health state of FLSCC in CRTS-III could be nondestructively real-time monitored by the AE technique. Meanwhile, the calculated fracture parameters of the FLSCC specimen can reflect the cracks stability of the specimen. This study can also present experimental and theoretical references for further studies on FLSCC in CRTS-Ⅲ under other types of loads.

On the deformation of CRTS-Ⅲ ballastless track during the casting process of self-compacting concrete: Numerical simulations and random forest-based prediction models

CRTS (China railway track system)-Ⅲ slab track is a main structural type of ballastless track in Chinse high-speed railway (HSR), which requires precise positioning of prefabricated concrete track slabs. However, the cast-in-place process of the self-compacting concrete (SCC) filling layer induces a large deformation as the flowing SCC generates an up-lift force on the bottom of the track slab. Currently, the deformation mechanism and influencing factors of the track slab during the SCC casting process have not been thoroughly studied. In this work, a fluid-solid interaction finite element model (FEM) is created to calculate the upward deformation of the CRTS-Ⅲ track slab caused by the flowing SCC. The main influencing factors, including the SCC’s casting height and speed, SCC’s viscosity, constraint stiffness of the limiting beams, and vertical temperature gradient, have been systematically analyzed and discussed. The relationship between the influencing factors and the track slab’s deformation is obtained. Furthermore, machine learning prediction models using random forest algorithms are developed to evaluate the deformation and up-lift force. A dataset comprising 603 calculation cases obtained from FEM simulations is used to train the prediction models. The random forest-based models developed in this study give an accurate estimation of the deformation and up-lift force based on the SCC properties and construction parameters. In addition, the feature importance of each influencing factor is obtained and studied. The findings of this study can provide guidance for the control of the deformation in CRTS-Ⅲ track slab during the SCC construction process.

Experimental study on interface performance of CRTS Ⅱ slab ballastless track under temperature loading

Interlayer interface damage poses a prevalent challenge in China Railway Track System (CRTS) Ⅱ slab ballastless tracks, with temperature playing a pivotal role in its occurrence. This study aims to scrutinize the mechanism of interlayer interface damage of track structure under temperature loading, vertical full-scale composite specimens were constructed for push-out and normal-tension model tests, and digital image correlation (DIC) technology was adopted to obtain the interlayer strain field distribution during loading and to get the mechanical property degradation, damage evolution law and damage mechanism of cement asphalt (CA) mortar layer interface under different temperatures. Based on the experimental study and fracture mechanics, the temperature cohesion damage model of the track slab-CA mortar interlayer interface was established. The results show that the bonding surface between the track slab and CA mortar layer is particularly susceptible to damage, and the interface damage exhibits "cold brittleness" and " thermal ductility" at low and high temperatures, respectively. Cohesion zone models (CZM) were constructed for both the normal and tangential interfaces at temperatures of 0 °C, 15 °C, 30 °C, 45 °C, and 60 °C. Furthermore, by defining field variables in the ABAQUS software, a temperature variation function describing key parameters of interface damage fracture behavior was integrated into the CZM, using defined field variables. The simulation results exhibited excellent agreement with the experimental findings.

Study on physical and mechanical properties of cement asphalt emulsified mortar under track slab

PurposeDuring the construction process of the China Railway Track System (CRTS) I type filling layer, the nonwoven fabric bags have been used as grouting templates for cement asphalt (CA) emulsified mortar. The porous structure of nonwoven fabrics endowed the templates with breathability and water permeability. The standard requires that the volume expansion rate of CA mortar must be controlled within 1%–3%, which can generate expansion pressure to ensure that the cavities under track slabs are filled fully. However, the expansion pressure caused some of the water to seep out from the periphery of the filling bag, and it would affect the actual mix proportion of CA mortar. The differences in physical and mechanical properties between the CA mortar under track slabs and the CA mortar formed in the laboratory were studied in this paper. The relevant results could provide important methods for the research of filling layer materials for CRTS I type and other types of ballastless tracks in China.Design/methodology/approachDuring the inspection of filling layer, the samples of CA mortar from different working conditions and raw materials were taken by uncovering the track slabs and drilling cores. The physical and mechanical properties of CA mortar under the filling layer of the slab were systematically analyzed by testing the electrical flux, compressive strength and density of mortar in different parts of the filling layer.FindingsIn this paper, the electric flux, the physical properties and mechanical properties of different parts of CA mortar under the track slab were investigated. The results showed that the density, electric flux and compressive strength of CA mortar were affected by the composition of raw materials for dry powders and different parts of the filling layer. In addition, the electrical flux of CA mortar gradually decreased within 90 days’ age. The electrical flux of samples with the thickness of 54 mm was lower than 500 C. Therefore, the impermeability and durability of CA mortar could be improved by increasing the thickness of filling layer. Besides, the results showed that the compressive strength of CA mortar increased, while the density and electric flux decreased gradually, with the prolongation of hardening time.Originality/valueDuring 90 days' age, the electrical flux of the CA mortar gradually decreased with the increase of specimen thickness and the electrical flux of the specimens with the thickness of 54 mm was lower than 500 C. The impermeability and durability of the CA mortar could be improved by increasing the thickness of filling layer. The proposed method can provide reference for the further development and improvement of CRTS I and CRTS II type ballastless track in China.

On the use of dispersion curves to determine the critical speed of railway tracks. Application to case studies

Trains may reach a so-called critical speed at which, in the absence of damping, the dynamic response of the entire railway infrastructure would grow without any bound. A train will have less impact on the track the more its speed is lower than the critical speed. Therefore, in terms of track maintenance, it is of vital importance to know the critical speed along the track before its construction.Following the results mathematically proved by Kausel et al. (2020), we present a procedure —referred to as the “CSC method”— to determine the critical speed of railway tracks. It is based on the dispersive characteristics of the railway track system, which consists of the track bed layers (including the ballast, subballast and form layers among others), the embankment and the foundation ground (which can be arbitrarily layered). We validate the CSC method by using measurements from the well-known real case of Ledsgard (Sweeden). This method is easier to be implemented than dynamic FEM models and requires less geotechnical parameters and computational time.The CSC method is applied to some case studies: We use it to estimate the critical speed of a typical high-speed line and to study the influence on the critical speed of (i) the height of the embankment and (ii) the presence and thickness of an upper ground layer with low shear wave velocity. In addition, the critical speed inferred for the typical high-speed line is corroborated with experimental results from a railway testing facility at 1:1 scale, which can be interpreted as further validation of the CSC method. Moreover, the robustness of this method is demonstrated by the fact that the trend of results from the latter calculations (cases i and ii) agrees with the expected ones.

Full-Scale Experimental and Field Investigations into Expansion Mechanism of Foamed Polyurethane and its Lifting Behaviors for Repair and Maintenance of Railway Slab Track Systems.

Excessive settlement of the subgrade seriously reduces the service quality of slab tracks and threatens trains' running safety. While the utilization of foamed polyurethane is recognized as an effective solution, previous research on its expansion mechanism and its impact on track lifting requires further refinement. Accordingly, a series of full-scale tests, including expansion force tests on foamed polyurethane with diverse qualities and lifting tests of polyurethane grouting with varied qualities on the track structure, have been conducted. The expansion development process of foamed polyurethane is meticulously elucidated, and key expansion parameters are analyzed. Simultaneously, this research explores the lifting behavior of foamed polyurethane grouting under the slab tracks, yielding new insights into essential lifting parameters for track formation repair and maintenance. Based on the experimental data, this study proposes new empirical formulas to comprehensively describe both the expansion mechanism of foam polyurethane and its lifting behavior under the slab tracks. The outcomes of this research offer a new breakthrough for the design of lifting mechanism for maintaining slab track structures through the utilization of foam polyurethane slurry grouting, such as determining the optimal grouting quantity. In addition, these results are instrumental to the evaluation of lifting effects and service life, enhancing the circular economy of railway track systems.

Investigating the fatigue performance of conventional reinforced concrete CRTS III ballastless track structures using a fatigue damage constitutive model

Compared to prestressed track structures, the mechanisms underlying fatigue degradation in conventional reinforced concrete track structures under high-cycle train loads remain elusive. This paper introduces a finite element model for CRTS (China Railway Track System) III slab ballastless track. In this model, fatigue damage constitutive relationships for both concrete and reinforcement are incorporated as material subroutines. The study focuses on investigating the fatigue characteristics of composite plate structures, which consist of track slabs and self-compacting concrete (SCC). An accelerated calculation method for high-cycle fatigue issues is utilized. Several key findings emerge from this study. First, the onset of fatigue cracks is observed on the lower surface of the SCC, directly beneath the applied load. These cracks tend to propagate laterally from the most critical location toward the slab edge. Second, a significant interrelationship exists between material fatigue degradation and stress redistribution. Traditional decoupled fatigue analysis methods are likely to overestimate the rate of fatigue evolution at critical points. Third, increasing the stiffness of geotextiles can partially optimize stress distribution within the track structures, thereby extending the time to initial cracking.

Research on crack propagation of CRTS III track slabs under train load

Microcracks may occur in Chinese Railway Track System type III (CRTS III) ballastless track slabs during service, and it is necessary to investigate their potential propagation under train load, which could lead to slab deterioration and affect the durability of the track structure. In this paper, based on the fracture mechanics theory, the stress intensity factors (SIFs) at the tips of transverse crack, longitudinal crack and vertical crack on the CRTS III track slabs under train load are solved by the extended finite element method (XFEM) in Abaqus software. The changes of SIFs at the crack tips during the passage of the train are analyzed, and the effects of the crack length and depth on the SIFs of the three types of cracks are discussed under train load. Crack growth rate is calculated using Paris' semi-empirical law to estimate slab life. The results show that the train load contributes to the propagation of transverse and vertical cracks in the vertical direction and inhibits the longitudinal cracks. When the middle of the sixth vehicle is above the crack, the SIFs at the tips of the crack reach their maximum values. The SIF of vertical cracks exceeds the fracture toughness at a certain depth. The fatigue load cycles calculated by Paris' semi-empirical law suggest that maintenance will not be required due to insufficient propagation under train load during service.

A predictive model based on the LSTM technique for the maintenance of railway track system

A predictive model based on the LSTM technique for the maintenance of railway track system

The influence of uneven frost heave and thermal conditions on the deformation and damage of slab track in seasonally frozen regions

To ensure the secure operation of high-speed trains in seasonally frozen regions, this paper investigates the deformation and failure patterns of slab tracks subjected to uneven frost heave and environmental issues. Utilizing our team’s previous research findings, finite element analysis software was employed to construct a mechanical transfer calculation model for the subgrade and slab track. This model was used to explore the relationship between uneven frost heave and slab track deformation at different time periods, along with the track structure’s damage behavior. In addition, comprehensive temperature field tests were conducted on the China railway track system (CRTS) III slab track, probing temperature variations, warping deformations, and stress distributions within the track structure. Finally, the interaction of uneven frost heave and thermal loads unveiled the interlayer debonding and stress characteristics of slab track structures across different months in seasonally frozen regions. The results revealed that the greater amplitude of frost heave and the smaller wavelength led to a higher change rate of rail irregularity. The uneven lateral deformation of the subgrade surface due to the sunny-shady slopes effect resulted in significant rail level irregularity of slab tracks. The combined impact of short-wavelength frost heave and temperature gradient loads emerged as the primary cause of macroscopic damage and stiffness degradation of concrete materials within slab track structures. These findings will help to understand the mechanical behavior of slab tracks in cold regions, thereby improving the quality of high-speed railway operations.

Experimental study of friction performance degradation in sliding layer of CRTS II slab track considering dust incursion

The track-bridge interaction force in the China Railway Track System II slab track can be significantly reduced due to the effect of the sliding layer, thus its friction performance is crucial for the operational safety of the track. However, because of the micro delamination between the base plate and bridge deck under certain conditions, the dust inevitably infiltrates the sliding layer. This study performed abrasion experiments to investigate the influence of dust incursion on the friction performance of the sliding layer. The experimental apparatus was designed to simulate repeated sliding and normal pressure between the base plate and the bridge under actual working conditions. Different sizes of dust particles were employed, and the friction performance, characterized by the friction coefficient and surface topography of the geomembrane, was obtained and analyzed. The experimental results show that the growth rate of the friction coefficient was 1.46–2.88 times greater than that without dust incursion. The results of this study can serve as a reference for the actual friction performance degradation of the sliding layer and shed light on maintenance decision-making.

Influences of cement asphalt emulsified mortar construction on track slab geometry status

PurposeThe construction of cement asphalt (CA) emulsified mortar can obviously disturb the slab status after the fine adjustment. To decrease or eliminate the influence of CA mortar grouting on track slab geometry status, the effects of grouting funnel, slab pressing method, mortar expansion ratio, seepage ratio and grouting area on China Railway Track System Type (CRTS I) track slab geometry status were discussed in this paper.Design/methodology/approachCombined with engineering practice, this paper studied the expansion law of filling layer mortar, the liquid level height of the filling funnel, the pressure plate device and the amount of exudation water and systematically analyzed the influence of filling layer mortar construction on the state of track slab. Relevant precautions and countermeasures were put forward.FindingsThe results showed that the track slab floating values of four corners were different with the CA mortar grouting and the track slab corner near CA mortar grouting hole had the maximum floating values. The anti-floating effect of “7” shaped slab pressing device was more efficient than fixed-joint angle iron, and the slab floating value could be further decreased by increasing the amount of “7” shaped slab pressing devices. After CA mortar grouting, the track slab floating pattern had a close correlation with the expansion rate and water seepage rate of CA mortar over time and the expansion and water seepage rate of the mortar were faster when the temperature was high. Furthermore, the use of strip CA mortar filling under the rail bearing platform on both sides could effectively reduce the float under the track slab, and it could also save mortar consumption and reduce costs.Originality/valueThis study plays an important role in controlling the floating values, CA mortar dosage and the building cost of projects by grouting CA mortar at two flanks of filling space. The research results have guiding significance for the design and construction of China's CRTS I, CRTS II and CRTS III track slab.