Abstract
Results of finite-element analyses calculating the undrained capacities of skirted circular foundations under uniaxial vertical, horizontal, and moment loading are presented. Parallel finite-element analyses using both the Tresca failure criterion and the modified cam clay (MCC) model are reported. The variations in capacity are presented as functions of embedment and soil-strength heterogeneity as a series of graphs. Closed-form formulas of uniaxial capacities are also provided. To account for the complexity in the results, a novel method of separating the contributions of soil above and beneath the skirt tip and for the constant and linearly varying components of the undrained shear-strength profile is outlined. This method can be used to estimate the undrained ultimate uniaxial capacity factors of skirted circular foundations in clay for any given embedment ratio and strength heterogeneity. Its versatility is also shown through validation against previously published embedded strip footing data. The results provide both equations for engineers to use in design and a database that can be used in future research to calculate and express the consolidated undrained capacity under combined loading.
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Acknowledgments
This work forms part of the activities of the Centre for Offshore Foundation Systems (COFS), which is supported by the Lloyd’s Register Foundation as a Centre of Excellence and now forms one of the primary nodes of the Australian Research Council (ARC) Centre of Excellence for Geotechnical Science and Engineering. Lloyd’s Register Foundation helps to protect life and property by supporting engineering-related education, public engagement, and the application of research.
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©2017 American Society of Civil Engineers.
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Received: Jun 24, 2016
Accepted: Dec 5, 2016
Published ahead of print: Mar 7, 2017
Published online: Mar 8, 2017
Published in print: Jul 1, 2017
Discussion open until: Aug 8, 2017
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