Microstructural evolution at sand–structure interface of suction caisson subjected to lateral cyclic loadings

Abstract

Suction caissons are being widely employed as a reliable and economic foundation to offshore wind farm. Previous studies are inconclusive in soil microstructural evolution around soil–structure. This article describes a half-caisson subjected lateral cyclic loading with the macro photography device (MPD). The microstructural probability entropy and corresponding quantification criterion are introduced to examine the effects of grain size distribution, grain orientation on monotonic, and post-cyclic moment capacities of suction caissons. The image-based results provide evidence of significant particle rearrangement occurred adjacent to the caisson wall. The variations of the grain size entropy and the orientation entropy with cycles were obviously affected by loading amplitudes, sand gradations, and position of the caisson interface, but less dependent with the loading frequency. Experimental results reveal the dominance of the grain size entropy over the moment capacity of suction caissons under different loading characteristics and sand samples. The half-model tests together with the MPD shed light on soil–structure behaviors with the microstructural evolution at the suction caisson interface.