Failure analysis of widened railway embankment with different reinforcing measures under heavy axle loads: A comparative FEM study

Lazorenko, Georgy; Kasprzhitskii, Anton; Kukharskii, A. V.; Кочур, А.Г.; Yavna, V. A.

doi:10.1016/j.treng.2020.100028

Cited by 12 publications

(6 citation statements)

References 31 publications

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“…The obtained values confirm the legitimacy of using a foamed concrete layer to strengthen the substrate, and thus reduce subgrade settlement, which is particularly important in the case of high-speed railways [ 102 , 103 , 104 , 105 , 106 ]. Moreover, this solution can be used as an alternative to other applied solutions to strengthen the substrate [ 15 , 107 , 108 ].…”

Section: Resultsmentioning

confidence: 99%

“…[ 7 ]). At present, as thermal insulation or reinforcement materials in sub-ballast or sub-base layers can be used various polymer materials e.g., expanded polystyrene (EPS) [ 8 ], polyurethane [ 9 ], extruded polystyrene (styrodur) [ 10 , 11 , 12 ], artificial aggregates, liapor with foam glass [ 13 , 14 ], and geosynthetic materials (geogrids, geo-mattresses) [ 15 , 16 ]. The expanded polystyrene (EPS) in contact with subsoil is also used as isolation under (shallow) foundation [ 17 , 18 ] and under road pavement foundation [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

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Experimental and Numerical Verification of the Railway Track Substructure with Innovative Thermal Insulation Materials

et al. 2021

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The article aims to present the modified structural composition of the sub-ballast layers of the railway substructure, in which a part of the natural materials for the establishment of sub-ballast or protective layers of crushed aggregate is replaced by thermal insulation and reinforcing material (layer of composite foamed concrete and extruded polystyrene board). In this purpose, the experimental field test was constructed and the bearing capacity of the modified sub-ballast layers’ structure and temperature parameters were analyzed. A significant increase in the original static modulus of deformation on the surface of composite foamed concrete was obtained (3.5 times and 18 times for weaker and strengthen subsoil, respectively). Based on real temperature measurement, it was determined the high consistency of the results of numerical analyses and experimental test (0.002 m for the maximum freezing depth of the railway line layers and maximum ±0.5 °C for temperature in the railway track substructure–subsoil system). Based on results of numerical analyses, modified railway substructure with built-in thermal insulating extruded materials (foamed concrete and extruded polystyrene) were considered. A nomogram for the implementation of the design of thicknesses of individual structural layers of a modified railway sub-ballast layers dependent on climate load, and a mathematical model suitable for the design of thicknesses of structural sub-ballast layers of railway line were created.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Verification of the Railway Track Substructure with Innovative Thermal Insulation Materials

et al. 2021

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“…The FEM generally produced the SF from the soil's shear strength properties, tan φ, and c with the shear strength steadily reduced up to the moment the soil is dissolved. Similarly, the interface strength is also decreased while the reduction in the strength parameters is controlled by the total coefficient as indicated in the following formula [23], [25]:…”

Section: Finite Element Methods (Fem)mentioning

confidence: 99%

Safety Factors Investigation Based on FEM and LEM Approach in Toll Road Embankment Slope

Fitri¹,

Fitria²

2022

cea

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The Pejagan-Pemalang toll road which is a Section II project was designed at different embankment heights on soft soil subgrade. The process involved investigating the slope stability of these embankments through the determination of the safety factor. This can be achieved using different methods such as the limit equilibrium method (LEM) and the finite element method (FEM) which are considered the standard approaches. However, the presentation of different numerous results for the safety factors (SF) in landslide calculations usually makes it difficult for the engineer to understand some uncertain conditions. Therefore, this study aims to determine the safety factors using LEM and FEM approaches at different conditions. The soil subgrade used was in SPT and three models of the properties were obtained. Moreover, a Geo-Studio program with Slope-W analysis was applied using the Morgenstern-Price for the LEM and PLAXIS for the FEM. The height was varied at 2 to 8m with the slope H: V at 1:1, 1:1.5, and 1:2. The simulation was conducted at three different levels of groundwater. The results showed that the height, embankment geometry, and groundwater levels were affected in the SF analysis using the two methods. It was also discovered in all categories that higher embankments had smaller SF while the higher angle of slope produced a higher SF. Furthermore, the properties of the soft soil were observed to have influenced the SF result as indicated by the narrow difference in the correlation between the embankment height and SF. The results of the LEM and FEM were also compared and the observations were explained. The findings of this study are expected to serve as a guide for engineers, especially those in road toll projects, to determine the optimum model needed to predict slope failure in embankments for toll roads.

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“…Te dynamic train load demands the selection of an appropriate material model for numerical analysis that can better apprehend the stress-strain behavior of embankments and subsoil. Previous studies have used linear elastic models [16,19], Mohr-Coulomb models [14,16,[20][21][22][23][24][25], hardening soil (HS) models [14,26], modifed Cam-Clay models [24], and hardening soil models with small strain stifness (HS-small) [18]. Among these, the HS-small model can simulate soil stifness at very small strains and its nonlinear dependency on strain amplitude [27], which is crucial to consider for predicting soil behavior under dynamic train loads.…”

Section: Introductionmentioning

confidence: 99%

Response Analysis of a Ballasted Rail Track Constructed on Soft Soil by 3D Modeling

Hoque

Aziz

Mallick

et al. 2023

Advances in Civil Engineering

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The displacement, stress, and strain distributions of railway embankments on the soft deltaic deposit of the Ganges–Brahmaputra floodplain are investigated. A numerical model developed in general-purpose finite element software is used to simulate the design train load on a deltaic deposit for a 100 km/hr rail speed. The numerical analysis analogy is grounded in the spring model, where a beam under the unit load is modeled based on the Winkler foundation model concept. In the moving load simulation on soil, the static point load relating to the axle load is assigned in the form of a dynamic multiplier, determined using auxiliary software. The calculated shear force in terms of the influence line is applied as a dynamic multiplier. The numerical results demonstrate that under a dynamic train load, the loose ballast undergoes larger and more erratic displacement than the subballast. Comparative analysis between varying subballast stiffnesses shows that stiffer subballast yields smaller displacements. Moreover, a high subballast stiffness can counterbalance the potential of forming permanent deformation by generating lower strains. However, a stiffer subballast does not play a prominent role in reducing the displacement of ballast or vertical stresses. The subgrade is found to carry the maximum load, withstanding the maximum vertical stress; thus, the importance of using an improved subgrade with higher stiffness is also observed. A greater subgrade stiffness improves its load-carrying capacity but fails to reduce the tension responsible for the lateral spreading of the soft subsoil. To reduce the high radial strain, the effects of improving the stiffness properties of two immediately adjacent soft soil layers are numerically investigated. The improvement of subsoil alone is effective in reducing the radial strain, whereas the improvement of both subgrade and subsoil produces further reductions. The critical train speed generating the maximum displacement is identified as 120 km/hr, and the dynamic velocity amplitude decreases with depth. Finally, an allowable limit of rail embankment settlement on a soft deltaic deposit is observed.

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Failure analysis of widened railway embankment with different reinforcing measures under heavy axle loads: A comparative FEM study

Cited by 12 publications

References 31 publications

Experimental and Numerical Verification of the Railway Track Substructure with Innovative Thermal Insulation Materials

Experimental and Numerical Verification of the Railway Track Substructure with Innovative Thermal Insulation Materials

Safety Factors Investigation Based on FEM and LEM Approach in Toll Road Embankment Slope

Response Analysis of a Ballasted Rail Track Constructed on Soft Soil by 3D Modeling

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