Bearing Capacity of Spatially Random Cohesive Soil Using Numerical Limit Analyses
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 137, Issue 11
Abstract
This paper describes a probabilistic study of the two-dimensional bearing capacity of a vertically loaded strip footing on spatially random, cohesive soil using numerical limit analyses (NLA-CD). The analyses use a Cholesky decomposition (CD) technique with midpoint discretization to represent the spatial variation in undrained shear strength within finite-element meshes for both upper- and lower-bound analyses and assumes an isotropic correlation length. Monte Carlo simulations are then used to interpret the bearing capacity for selected ranges of the coefficient of variation in undrained shear strength and the ratio of correlation length to footing width. The results are compared directly with data from a very similar study in which bearing capacity realizations were computed using a method of local average subdivision (LAS) in a conventional displacement-based finite-element method (FEM-LAS). These comparisons show the same qualitative features but suggest that the published FEM calculations tend to overestimate the probability of failure at large correlation lengths. The NLA method offers a more convenient and computationally efficient approach for evaluating effects of variability in soil strength properties in geotechnical stability calculations.
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Acknowledgments
The writers are grateful to the Japanese Ministry of Education (MEXT) for providing postdoctoral support to the first writer at MIT. The writers are also grateful to Dr. John Christian for his detailed review and advice in editing this paper.
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Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 137 • Issue 11 • November 2011
Pages: 989 - 996
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Oct 12, 2007
Accepted: Mar 8, 2011
Published online: Mar 10, 2011
Published in print: Nov 1, 2011
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