Compressed air energy storage (CAES), in which surplus energy is utilized for compressing ambient air that can be released later to provide necessary energy, is being actively pursued in a last decade. This technology has a potential to strengthen the efficiency of renewable energy generation, such as solar and wind power. In addition to the large-scale energy storages, CAES can be operated at a small-scale to support facilities such as residential buildings. In this case, closed-ended steel piles can serve to provide the space where pressurized air is stored during off-peak periods, which leads to an idea of small-scale CAES pile. To continue pursuing the idea of using pile foundation system as an energy storage vessel, we need to examine long-term stability of CAES pile. In this pilot study, we investigate a finite element model of an axisymmetric CAES pile that is subject to the internal uniform pressurization while supporting a constant structural load. Long-term stability of the CAES pile is assessed from the first 10 pressurization-depressurization cycles at the various initial dead load conditions. Elasto-perfectly-plastic constitutive law is employed at the pile-soil interface for simplicity. We are able to observe that vertical displacement of the CAES pile accumulates with negligible radial deformation as the number of pressure cycle increases.
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