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Advances in Materials Science and Engineering
Volume 2015, Article ID 540621, 6 pages
http://dx.doi.org/10.1155/2015/540621
Research Article

Micromechanism Underlying Nonlinear Stress-Dependent of Clays at a Wide Range of Pressures

1State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining and Technology, Xuzhou 221116, China
2School of Mechanics & Civil Engineering, China University of Mining and Technology, Xuzhou 221116, China

Received 7 April 2015; Revised 18 May 2015; Accepted 21 May 2015

Academic Editor: Ana S. Guimarães

Copyright © 2015 Xiang-yu Shang 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

In order to investigate the mechanism underlying the reported nonlinear at-rest coefficient of earth pressure, of clays at high pressure, a particle-scale model which can be used to calculate vertical and horizontal repulsion between clay particles has been proposed. This model has two initial states which represent the clays at low pressure and high pressure, and the particles in this model can undergo rotation and vertical translation. The computation shows that the majority of particles in a clay sample at high pressure state would experience rotation during one-dimensional compression. In addition, rotation of particles which tends to form a parallel structure causes an increase of the horizontal interparticle force, while vertical translation leads to a decrease in it. Finally, the link between interparticle force, microstructure, and macroscopic is analyzed and it can be used to interpret well the nonlinear changes in with both vertical consolidation stress and height-diameter ratio.