Experimental and Numerical Study of Micropiles to Reinforce High Railway Embankments

AbstractThe construction of railway embankments on loose beds using reinforcing elements results in a modification of the embankments slope, which significantly reduces the amount of earthworks. In addition, reinforcement of both bed and embankment is essential to increase the load-bearing capacity...

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Bibliographic Details
Published in:International journal of geomechanics 2013-12, Vol.13 (6), p.729-744
Main Authors: Esmaeili, Morteza, Nik, Morteza Gharouni, Khayyer, Farid
Format: Article
Language:English
Subjects:
Axial strain
Bearing capacity
Embankments
Mathematical models
Numerical analysis
Railways
Sensitivity analysis
Slopes
Technical Papers
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Summary:AbstractThe construction of railway embankments on loose beds using reinforcing elements results in a modification of the embankments slope, which significantly reduces the amount of earthworks. In addition, reinforcement of both bed and embankment is essential to increase the load-bearing capacity and control the settlements. A solution for high railway-embankment stabilization and enhancing the operational axle load is the use of micropiles in the embankment toe to transmit the applied loads to the firm underlying layers and avoid the deep sliding of loose subgrade. This paper presents three experimental models of embankments of 10 m in height on a scale of 1/20 to set up a number of loading tests: one based on a non-reinforced embankment and two others based on reinforced embankments that are stabilized with two different arrangements of micropiles. During laboratory tests, the data, including the load-bearing capacity of embankments, displacements of embankment crest and bed surface, and axial strain of micropiles were measured using the instrumentation tools. In the next step, three numerical models were developed by using the PLAXIS-3D code based on the FEM. Then, a comparison was made between the experimental and numerical data to verify the outputs of the numerical analyses. In the procedure of numerical analyses, elastoplastic behaviors of embankment material and bed were defined based on the Mohr-Coulomb failure criterion, and micropiles were considered as linear elastic elements. Finally, after accomplishing a series of sensitivity analyses on the geometric parameters of micropiles, their efficiency factor was classified in the process of arrangement optimization.
ISSN:1532-3641
1943-5622
DOI:10.1061/(ASCE)GM.1943-5622.0000280