TY - JOUR A1 - Cuéllar, Pablo A1 - Georgi, Steven A1 - Baeßler, Matthias A1 - Rücker, Werner T1 - On the quasi-static granular convective flow and sand densification around pile foundations under cyclic lateral loading T2 - Granular matter N2 - The saturated sand surrounding an offshore pile foundation under quasi-static cyclic lateral load can show the physical phenomena of macromechanical densification and convective granular flow. Based on the results from physical model tests at different geometrical scales, this paper provides a certain quantification of such phenomena and discusses their causes and consequences. The progressive sand densification leads to subsidence of the soil surface and a significant stiffening of the pile behaviour. Conversely, the ratcheting convective motion of two closed cells of soil beneath the pile-head is responsible for an endless grain migration at the soil surface, the inverse grading of the convected material and a direct shear of the sand at the distinct boundary of the revolving soil domain. In this respect, and from a macromechanical perspective considering the soil as a continuum, it appears that the convecting material tends to follow gradient lines of shear stress during its ratcheting motion. Concluding the paper, the practical relevance of these phenomena and their extrapolation to other conditions are briefly discussed. PB - Springer CY - Berlin ; Heidelberg KW - Offshore pile foundation KW - Cyclic loading KW - Ratcheting KW - Granular convection KW - Densification PY - 2012 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/25405 AN - OPUS4-25405 SN - 1434-5021 SN - 1434-7636 VL - 14 IS - 1 SP - 11 EP - 25 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany