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Advances in Materials Science and Engineering
Volume 2017, Article ID 6241479, 15 pages
https://doi.org/10.1155/2017/6241479
Research Article

Permanent Deformation Characteristics of Coarse Grained Subgrade Soils under Train-Induced Repeated Load

1School of Civil Engineering, Harbin Institute of Technology, Heilongjiang, Harbin 150090, China
2School of Transportation Science and Engineering, Harbin Institute of Technology, Heilongjiang, Harbin 150090, China

Correspondence should be addressed to Peng Li; moc.361@pl_tih

Received 30 August 2016; Revised 12 December 2016; Accepted 26 December 2016; Published 6 February 2017

Academic Editor: Donato Sorgente

Copyright © 2017 Xianzhang Ling et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper presents the results of a laboratory experiment that aimed to characterize the permanent deformation behavior of coarse grained soils. To evaluate the effects of the cyclic stress amplitude, initial mean stress, and initial stress ratio on the permanent axial deformation, six series of repeated load triaxial tests were performed. The results indicate that permanent deformation of coarse grained soils increased with increasing cyclic stress amplitude. In particular, for relative low cyclic stress levels, accumulation rate of permanent deformation decreased progressively with number of cycles and eventually reached an equilibrium state. The initial stress ratio was also found to obviously facilitate the buildup of axial deformation since it means higher deviatoric stress as the mean pressure kept constant. As the initial stress ratio was less than the slope of static failure line, the experimental results indicated that the increase of initial mean stress enhanced the capability of resisting deformation. A simplified mechanistic empirical prediction model was proposed, which predicted the permanent deformation as product of four independent functions about cyclic stress amplitude, initial mean stress, initial stress ratio, and number of load cycles. Satisfactory predictions of the permanent deformation behavior of coarse grained soils were obtained with the proposed model.