TY - GEN

T1 - A scaling approach for the behaviour of different sand materials in cyclic direct simple shear tests

AU - Goldau, Norman

AU - Saathoff, Jann Eike

AU - Achmus, Martin

N1 - Publisher Copyright: © 2024 by the International Society of Offshore and Polar Engineers (ISOPE).

PY - 2024

Y1 - 2024

N2 - The foundations of offshore structures are subjected to cyclic loads from wind and waves. Cyclic loads can lead to an accumulation of deformations in the saturated soil as well as to an accumulation of excess pore water pressures with corresponding reductions in strength or bearing capacity. The latter is of particular importance under the conditions of a storm event. To assess excess pore water pressure accumulation, cyclic laboratory tests must usually be performed. From such tests, contour plots can be developed that describe excess pore pressure accumulation as a function of dimensionless amplitude and mean value of cyclic shear stress (cyclic stress ratio CSR and mean stress ratio MSR, respectively). Herein, the CSR value which leads to liquefaction after 10 cycles can be used as a parameter characterizing the cyclic soil response. Experimental results documented in the literature suggest that contour plots of different sandy soils can be transformed into each other if the experimental results are normalized to this value. In the presented work, different sandy soils at variable relative densities are investigated in a cyclic direct simple shear device to verify and quantify the above-mentioned assumption. Artificial soils consisting of glass beads are additionally used to investigate the influence of grain shape. A scaling approach to derive the cyclic response with a small number of cyclic laboratory tests is presented.

AB - The foundations of offshore structures are subjected to cyclic loads from wind and waves. Cyclic loads can lead to an accumulation of deformations in the saturated soil as well as to an accumulation of excess pore water pressures with corresponding reductions in strength or bearing capacity. The latter is of particular importance under the conditions of a storm event. To assess excess pore water pressure accumulation, cyclic laboratory tests must usually be performed. From such tests, contour plots can be developed that describe excess pore pressure accumulation as a function of dimensionless amplitude and mean value of cyclic shear stress (cyclic stress ratio CSR and mean stress ratio MSR, respectively). Herein, the CSR value which leads to liquefaction after 10 cycles can be used as a parameter characterizing the cyclic soil response. Experimental results documented in the literature suggest that contour plots of different sandy soils can be transformed into each other if the experimental results are normalized to this value. In the presented work, different sandy soils at variable relative densities are investigated in a cyclic direct simple shear device to verify and quantify the above-mentioned assumption. Artificial soils consisting of glass beads are additionally used to investigate the influence of grain shape. A scaling approach to derive the cyclic response with a small number of cyclic laboratory tests is presented.

KW - accumulation

KW - CDSS test

KW - contour plots, cyclic loading

KW - grain size distribution

KW - offshore

KW - scaling

UR - http://www.scopus.com/inward/record.url?scp=85200778350&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:85200778350

SN - 9781880653784

T3 - Proceedings of the International Offshore and Polar Engineering Conference

SP - 1205

EP - 1211

BT - Proceedings of the 34th International Ocean and Polar Engineering Conference, 2024

PB - International Society of Offshore and Polar Engineers

T2 - 34th International Ocean and Polar Engineering Conference, ISOPE 2024

Y2 - 16 June 2024 through 21 June 2024

ER -