Centrifugal model testing of foundation piles in axial loading

Citation

Christenson, John Eric (1982) Centrifugal model testing of foundation piles in axial loading. Engineer's thesis, California Institute of Technology. doi:10.7907/FDZ3-F478. https://resolver.caltech.edu/CaltechETD:etd-09142006-140129

Abstract

The recent growth in oil production from offshore flelds has stimulated demand for improvements in the analysis and prediction of foundation pile behavior. The traditional, empirical means of determining pile behavior under load, on-site load testing, is prohibitively expensive offshore. Moreover, extrapolation from experience with pile performance on land is liable to significant error, both because of the relatively diverse load-bearing requirements placed on piles by ocean structures, and the great size of these piles. Several classes of modeling and analytical techniques which have received extensive attention in the geotechnical literature of the past decade are described and evaluated. Pile load tests in the fleld have been simulated using centrifugal modeling. Procedures and results are reported of six load tests on cylindrical steel piles embedded to depths ranging from 54 to 183 feet in dry and saturated sand and saturated silt soils. The strain gauge-instrumented piles were subjected to extensive sequences of axial loading, including loading to bearing capacity failure and cyclic loading. Graphs showing the distribution of axial force in the pile were produced for all tests, and soil-pile interaction was interpreted by means of "t-z diagrams", i.e., graphs of soil-pile shear stress versus pile axial displacement at particular depths along the pile. The accuracy of the model test results is assessed by comparing them with the published results of a matching full-scale test. The work demonstrates the feasibility of using centrifugal modeling to investigate the behavior of large piles under a broad range of axial loadings.

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