Settlement of Railway Track on Reinforced Ballast Overlain by Clayey

Fattah, Mohammed Y.

doi:10.26650/jtl.2020.0014

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…ey showed that by an increase of the amplitude load and the load frequency, consequently, the settlement of the subgrade layer settlement is decreased. Other studies also indicated that geogrid reinforcement improves the railway track by reducing the dynamic frequency response and settlement [46,47]. Fattah et al [48] also focused on investigating the stress distribution from railway track over geogrid reinforced ballast underlain by clay.…”

Section: Literature Reviewmentioning

confidence: 99%

Modeling Dynamic Frequency Response on Slab Track of Shinkansen Railway Based on Finite Element Method

Gholizadeh

Aghayan

Hadadi

2022

Advances in Civil Engineering

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The use of slab tracks in lieu of ballast tracks has introduced new dimensions in track dynamics in high-speed railways. To improve the performance of slab tracks under dynamic frequency responses caused by loads on the Shinkansen railway, the present study aimed to investigate the effect of mechanical properties of track components, including the elasticity modulus and thickness on the resonance frequency of the vertical dynamic responses using the finite element method. Such responses included receptance and decay rate in the asphalt bearing layer (ABL), hydraulically bonded layer (HBL), and concrete bearing layer (CBL). In addition, the study sought to select the optimal layer as an effective layer in the view of reducing the resonance frequency of dynamic responses in comparison with the general model. Based on the data regarding the effects of elasticity modulus and thickness of slab track layers on the resonance of the dynamic frequency responses under the amplitude loads, by changing the load from 20 to 25 tons over the slab track, the receptance under the modulus and thickness change increased up to 34 and 29%. Moreover, the decay rate under the modulus and thickness change increased up to 31 and 37%. Accordingly, by increasing the load amplitude, the CBL and HBL showed lower dynamic responses than other layers. Thus, CBL and HBL were selected as the optimum layers for improving the performance of the slab track of the Shinkansen railway.

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Section: Literature Reviewmentioning

confidence: 99%

Modeling Dynamic Frequency Response on Slab Track of Shinkansen Railway Based on Finite Element Method

Gholizadeh

Aghayan

Hadadi

2022

Advances in Civil Engineering

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“…The laboratory work carried out by Fattah, Mahmood, and Aswad (2020, 2022) consisted of laboratory model tests to investigate the reduction in the compressibility and stress distribution induced in soft and stiff clay under a ballast railway reinforced by geogrid reinforcement subjected to dynamic load of half sine wave shape. It was concluded that the amount of settlement increased with increasing the load amplitude, there is a sharp increase in settlement up to the cycle 500 and after that, there is a gradual increase to level out between 2,500 and 4,500 cycles depending on the load frequency.…”

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Experimental and numerical settlement analysis of railway track over geogrid reinforced ballast

Fattah,

Mahmood,

Aswad

2024

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PurposeThe main objective of the present research is to investigate the benefits of using geogrid reinforcement in minimizing the rate of deterioration of ballasted rail track geometry resting on soft clay and to explore the effect of load amplitude, load frequency, presence of geogrid layer in ballast layer and ballast layer thickness on the behavior of track system. These variables are studied both experimentally and numerically. This paper examines the effect of geogrid reinforced ballast laying on a layer of clayey soil as a subgrade layer, where a half full scale railway tests are conducted as well as a theoretical analysis is performed.Design/methodology/approachThe experimental tests work consists of laboratory model tests to investigate the reduction in the compressibility and stress distribution induced in soft clay under a ballast railway reinforced by geogrid reinforcement subjected to dynamic load. Experimental model based on an approximate half scale for general rail track engineering practice is adopted in this study which is used in Iraqi railways. The investigated parameters are load amplitude, load frequency and presence of geogrid reinforcement layer. A half full-scale railway was constructed for carrying out the tests, which consists of two rails 800 mm in length with three wooden sleepers (900 mm × 90 mm × 90 mm). The ballast was overlying 500 mm thick clay layer. The tests were carried out with and without geogrid reinforcement, the tests were carried out in a well tied steel box of 1.5 m length × 1 m width × 1 m height. A series of laboratory tests were conducted to investigate the response of the ballast and the clay layers where the ballast was reinforced by a geogrid. Settlement in ballast and clay, was measured in reinforced and unreinforced ballast cases. In addition to the laboratory tests, the application of numerical analysis was made by using the finite element program PLAXIS 3D 2013.FindingsIt was concluded that the settlement increased with increasing the simulated train load amplitude, there is a sharp increase in settlement up to the cycle 500 and after that, there is a gradual increase to level out between, 2,500 and 4,500 cycles depending on the load frequency. There is a little increase in the induced settlement when the load amplitude increased from 0.5 to 1 ton, but it is higher when the load amplitude increased to 2 ton, the increase in settlement depends on the geogrid existence and the other studied parameters. Both experimental and numerical results showed the same behavior. The effect of load frequency on the settlement ratio is almost constant after 500 cycles. In general, for reinforced cases, the effect of load frequency on the settlement ratio is very small ranging between 0.5 and 2% compared with the unreinforced case.Originality/valueIncreasing the ballast layer thickness from 20 cm to 30 cm leads to decrease the settlement by about 50%. This ascertains the efficiency of ballast in spreading the waves induced by the track.

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A Review of Railway Track Laboratory Tests with Various Scales for Better Decision‐Making about More Efficient Apparatus Using TOPSIS Analysis

Gilani

Habibzadeh

Hosseinian

et al. 2022

Advances in Civil Engineering

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Improving the performance of railways depends on increasing their efficiency and the speed of locomotives, which is provided by improving the infrastructure of railways. Therefore, in various studies, researchers seek to modify ballast materials, sleepers and rails, or to study various geometric and environmental conditions in order to reduce the existing weaknesses of railways. Therefore, in order to evaluate the above conditions, various tests should be performed on railways. Some of the tests take place in the field when the train is passing. However, these tests have various limitations and endanger the safety of researchers and are associated with difficulties. Therefore, many tests are performed using various apparatuses on a laboratory scale. In this study, by reviewing different apparatuses used by researchers to simulate loading on the railway, they were compared and by examining different criteria such as loading type, different loading directions, scale of apparatuses, static and dynamic simulated loads and other environmental and geometric conditions, the best apparatuses on a laboratory scale are recommended for simulating vertical, longitudinal and lateral loads and measuring noise and vibration. By the use of TOPSIS analysis on 16 introduced apparatuses from reviewing different studies, it was found that the scaled railway track model had the first rank among different apparatuses and by modifying the weaknesses of this apparatus, it can be turned into the most comprehensive laboratory apparatus to simulate the loading of railway tracks with a scale of 1 : 5. Among the introduced apparatuses, wheel on roller test rig and roller rig had the second and third ranks, respectively, the apparatuses of which usually have a scale of 1 : 5 and deal with the interaction between the rail and the wheel and the impact of the vehicle on the railway track.

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Settlement of Railway Track on Reinforced Ballast Overlain by Clayey

Cited by 3 publications

References 4 publications

Modeling Dynamic Frequency Response on Slab Track of Shinkansen Railway Based on Finite Element Method

Modeling Dynamic Frequency Response on Slab Track of Shinkansen Railway Based on Finite Element Method

Experimental and numerical settlement analysis of railway track over geogrid reinforced ballast

A Review of Railway Track Laboratory Tests with Various Scales for Better Decision‐Making about More Efficient Apparatus Using TOPSIS Analysis

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