Effect of Sand Columns on the Undrained Load Response of Soft Clays
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 136, Issue 9
Abstract
When sand columns are used as vertical drains in soil improvement schemes, the possible reinforcing role that these columns can play in regards to improving the bearing capacity is usually neglected in design. The objective of this paper is to evaluate the degree of improvement in the mechanical properties of soft clays in practical applications involving the use of sand drains or sand columns in clayey soils. For this purpose, 32 isotropically consolidated undrained triaxial tests were performed on normally consolidated kaolin specimens. The parameters that were varied were the diameter of the sand columns, the height of the columns, the type of columns (geotextile encased versus nonencased), and the effective confining pressure. Test results indicated that sand columns improved the undrained strength significantly even for area replacement ratios that were less than 18%. The increase in undrained strength was accompanied by a decrease in pore pressure generation during shear and an increase in Young’s modulus. The drained shear strength parameters were found to be relatively unaffected by the sand column reinforcement, except for fully penetrating columns with high area replacement ratios.
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Acknowledgments
The writers would like to acknowledge the support of the University Research Board (URB) at the American University of Beirut (AUB) for funding this research program.
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Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 136 • Issue 9 • September 2010
Pages: 1263 - 1277
Copyright
© 2010 ASCE.
History
Received: Feb 12, 2009
Accepted: Jan 17, 2010
Published online: Jan 25, 2010
Published in print: Sep 2010
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