Numerical analysis for mechanical behavior of pipe pile utilized for compressed air energy storage

Compressed air energy storage (CAES) technology has recently re-emerged due to ever-increasing energy demand. In particular, a pipe pile, where the compressed air could be stored inside the pile using a surplus energy during off-peak hours and released later for electricity generation, (hereafter referred to as "CAES pile") has been lately receiving attentions. To continue pursuing the idea of using pile foundation system as an energy storage vessel, the effect of pile-soil interactions during internal pressurization on foundation stability needs to be investigated. This paper investigates the behavior of a closed-ended steel pipe pile subjected to the internal pressure using axisymmetric finite element analysis. Special emphases are placed on the investigation of (1) pile head movement; and (2) developments of a longitudinal stress in pile under the pressurization. Results from the numerical analyses indicate that the magnitudes of the structural load applied at the pile head before pressurization play a major role in the mechanical behavior of the CAES pile. It is further observed that the changes in pile head displacements due to the internal pressurization are not significant and the longitudinal stress developed in the CAES pile does not exceed the yield strength of the material.