Upper-Bound Analysis of Nγ and Failure Mechanisms of Multiple Equally Spaced Strip Footings
Publication: International Journal of Geomechanics
Volume 17, Issue 9
Abstract
This paper investigates the ultimate bearing capacity factor (Nγ) and failure mechanisms of multiple rough strip footings with equally clear spacing (S) placed on pure sand using the upper-bound finite-element method with rigid translatory moving elements (UBFEM-RTME). Parametric analysis is performed by varying the dimensionless clear spacing (S/b) and the sand friction angle (ϕ), and all footings are assumed to be loaded to failure simultaneously with identical bearing loads. The critical spacing distance (Scr/b) and Nγ increase continuously with the increase in ϕ. With the S/b decreasing from Scr/b, the Nγ values are found to increase slightly before a rapid increase. The obtained failure mechanisms are primarily composed of mesh-like rigid blocks and a completely curved trapped wedge below the footing base. The relative movement of blocks around footing edges becomes particularly intensive, especially for closely spaced footings and sand with high values of ϕ.
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Acknowledgments
This work was sponsored by the Chinese National Natural Science Foundation (No. 51478477) and Innovation-Driven Project of Central South University (No. 2016CX012). The authors are grateful to these institutions for their support.
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Published In
International Journal of Geomechanics
Volume 17 • Issue 9 • September 2017
Copyright
© 2017 American Society of Civil Engineers.
History
Received: Sep 22, 2016
Accepted: May 3, 2017
Published online: Jul 13, 2017
Published in print: Sep 1, 2017
Discussion open until: Dec 13, 2017
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