UC San Diego

This paper presents the results from a series of centrifuge tests to understand the strain distribution in semi-floating energy foundations in dry Nevada sand during mechanical loading and foundation heating. In addition to the details of the model reinforced-concrete energy foundation, the results from 1-g thermo-mechanical characterization tests are presented. The centrifuge-scale tests involve application of an axial load to the head of the foundation (in load-control conditions) then circulation of a heat exchange fluid through embedded tubing to bring the foundation to a constant temperature. During this time, the axial strains are measured using embedded strain gages, and the soil and foundation temperatures and thermal and thermo-mechanical head displacements are monitored. Loading tests to failure were then performed on the foundations to characterize the impact of temperature on the load-settlement curve. The information from the tests permits definition of soil-structure interaction parameters for dry sands under realistic stress states. Different from previous studies on unsaturated silt, no change in ultimate side shear resistance was observed with increasing temperature. The thermal strains are relatively constant with depth and are close to free expansion. © 2014 Taylor & Francis Group.