Effects of a large number of cycles on pile shaft resistance analyzed at the grain scale using x-ray tomography
Univ. Grenoble Alpes, CNRS, Grenoble INP, 3SR, F-38000 Grenoble, France
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Published online: 30 June 2017
This study presents the results of laboratory-scale cyclic loading tests performed on an instrumented pile in sand using x-ray micro tomography and three-dimensional (3D) image analysis techniques. The macroscopic behaviour of sand-pile interface shows a two–phases evolution during cycles with a non negligible increase of shaft friction in the second phase. A discrete version of Digital Image Correlation (DIC) is employed to analyze quantitatively the mechanisms occurring at the grain scale. Using segmented images this method is able to correlate and follow each grain individually between two configurations. Displacement fields are measured and compared for different amounts of cycles. Grain breakage and density evolution are investigated using grey level measurements. The results provide a better understanding of the phenomena observed at the macroscale for a high number of load cycles.
© The Authors, published by EDP Sciences, 2017
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