Full-Scale Field Study on Effect of Grouting Methods on Bond Strength of Hollow-Bar Micropiles
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 144, Issue 12
Abstract
Self-drilled hollow bar micropiles are more popular for soil improvement projects than the use of the traditional solid bar system because they decrease construction costs and time. Little research has been published about the load-deformation behavior of hollow bar micropiles; thus, the effect of installation techniques and the nature of the surrounding ground on their bond strength remains unverified. The current study proposes three grouting methods to test the load-displacement behavior of hollow-bar micropiles in both clay and gravel. A field study was performed by installing 21 full-scale tests on hollow bar micropiles at two sites. Time-dependent grouting methods were used to evaluate the grout–ground bond strength. The observed load-displacement behavior indicated that the induced bond diameter of the hollow-bar micropiles was greater than the results of theoretical calculations and that their estimated bond strength was greater than the values recommended in existing codes. Moreover, elastic behavior was greater in micropiles which were grouted at higher drilling and injection durations and sequences.
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Acknowledgments
The authors greatly appreciate the support of Samanpey Soil Improvement Services and the use of their equipment during the field study.
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Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 144 • Issue 12 • December 2018
Copyright
©2018 American Society of Civil Engineers.
History
Received: Sep 3, 2017
Accepted: Jun 12, 2018
Published online: Sep 25, 2018
Published in print: Dec 1, 2018
Discussion open until: Feb 25, 2019
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