Experimental Investigation of Bucket Foundations Subjected to Vertical Pullout Loading in Sand

The pullout characteristics of bucket foundations installed in sand were investigated through a set of 1g experiments. The primary focus of the study was to investigate the influence of drainage conditions on bucket foundations during pullout loading. Loading rates within the range of 0.002 N/s to 4.1 N/s were applied during the experimental tests while utilizing polycarbonate model buckets. The research encompassed investigations into the generation of suction pressure at both the lid and tip of the bucket. As the loading rate increased, both the pullout load and suction pressure demonstrated a corresponding increase. To classify the drainage condition based on the test cases, a drainage factor which takes into account the pullout rate and the inflow velocity was introduced. Based on the proposed classification factor, the drainage conditions at the pullout capacity were categorized as undrained, partially drained, and drained.