Numerical Study of Shear Stress Distribution for Discrete Columns in Liquefiable Soils
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 140, Issue 3
Abstract
Discrete columns, such as stone and soil-cement columns, are often used to improve the liquefaction resistance of loose sandy ground potentially subjected to strong shaking. The shear stress reduction in the loose ground resulting from the reinforcing effect of these stiffer discrete columns is often considered as a contributing mechanism for liquefaction mitigation. Current design practice often assumes that discrete columns and soil deform equally in pure shear (i.e., shear strain–compatible deformation). In addition, because the discrete column is stiffer than the soil, it is assumed to attract higher shear stress, thereby reducing the shear stress in the surrounding soil. In this paper, shear stress reduction in liquefiable soils and shear strain distribution between liquefiable soil and discrete columns along with the potential of development of tensile cracks is investigated using three-dimensional linear elastic, finite-element analysis. Parametric analyses are performed for a range of geometries, relative stiffness ratios, and dynamic loadings. These linear elastic results provide a baseline against which future nonlinear modeling results can be compared, but they are also sufficient for demonstrating that shear stress reductions are far less than predicted by the assumption of shear strain compatibility. These numerical results are consistent with those of other researchers and further call into question the appropriateness of the strain-compatibility assumption for design.
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Acknowledgments
This research is funded by the Oregon DOT (ODOT), the Pacific Earthquake Engineering Research (PEER) Center, and Hayward Baker Inc. Their support is gratefully acknowledged. Authors are also thankful to Prof. Russell A. Green and Dr. Juan I. Baez for their comments and suggestions for this research.
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Information & Authors
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 140 • Issue 3 • March 2014
Copyright
© 2013 American Society of Civil Engineers.
History
Received: May 2, 2012
Accepted: May 24, 2013
Published online: May 27, 2013
Published in print: Mar 1, 2014
Discussion open until: May 2, 2014
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