ABSTRACT
Soils in the vicinity of the foundations of offshore energy systems are subjected to cyclic stresses arising from repeated environmental loads. Long-term application of such loading alters the surrounding soil’s strength and deformation characteristics and subsequently may put the performance of such systems at risk. The deformation of soil i.e., strain accumulation depends on both the soil parameters and the loading conditions. This paper presents the findings from an experimental study that focuses on strain accumulation in calcareous sands subjected to long-term cyclic loading. A series of drained cyclic triaxial tests were performed on saturated calcareous sand specimens up to 10,000 loading cycles. The influence of cyclic stress amplitude and sand density on the strain accumulation is investigated. The experimental results show an increase in strain accumulation with increasing cyclic stress amplitude and void ratio. The formulations of the High Cycle Accumulation Model are calibrated based on the experimental results. The test results provide valuable information on the deformation characteristics of the calcareous sands, which can be used to predict the performance of offshore structures under cyclic loads. The triaxial test results also provide a very useful database for calibrating advanced soil models to accurately assess the performance and behavior of the foundations of offshore energy systems.
