Settlement of deep footings in reconstituted sand

• Published in: Canadian geotechnical journal Vol. 56; no. 3; pp. 449 - 459
• Main Authors: Bagbag, A.A, Lehane, B.M, Doherty, J.P
• Format: Journal Article
• Language: English
• Published: Ottawa NRC Research Press 01-03-2019; Canadian Science Publishing NRC Research Press
• Subjects: Ageing; Aging; Circular plates; Cone penetration tests; Decompression chambers; essais de laboratoire; Finite element analysis; Finite element method; footing; Full scale tests; Geological research; in situ tests; laboratory tests; Land subsidences; Load tests; Physical tests; Plaques; Plate tectonics; Pressure chambers; Pressuremeter tests; sable; Sand; Sand & gravel; Sands; semelles; settlement; Stiffness; Studies; tassement; Tests; tests in situ; Vertical loads
• ISSN: 0008-3674; 1208-6010
• DOI: 10.1139/cgj-2017-0574

The paper examines methods for predicting the settlement of deep footings in reconstituted sand. Results from vertical load tests on deep circular plates within a laboratory pressure chamber are interpreted using data from triaxial tests, cone penetration tests (CPTs), and pressuremeter tests obtained for the same reconstituted sand. A simple nonlinear CPT-based relationship is shown to match the response observed in the plate tests and be consistent with finite element analyses as well as other comparable physical tests. The relationships between foundation stiffness and the sand’s small-strain stiffness, its stiffness at 50% mobilized strength, and its response to pressuremeter loading are also explored. Comparisons with full-scale tests in the field reveal a strong effect of ageing on foundation stiffness, which appears to be better captured by small-strain stiffness than CPT end resistance. Measurements confirm that vertical loading of a deep plate is analogous to the expansion of a spherical cavity.