Proposed Simplified Seismic Design for Energy Storage Facilities: Underground Structures

The rapid growth of the hydrogen industry, driven by global decarbonization efforts, has intensified the need for safe and large-capacity storage systems. Although hydrogen is one of the most abundant elements on Earth, its storage remains technically challenging due to its chemical reactivity and stringent containment requirements. Previous research has primarily emphasized the material-level behavior of polymer liners, composites, and metal alloys because chemical compatibility plays a critical role in aboveground high-pressure tanks. However, for underground storage systems, long-term structural stability is governed not only by material performance but also by the geo-mechanical behavior of deep rock masses. This study proposes a seismic design approach for Lined Rock Caverns (LRCs), a deep underground storage concept capable of sustaining high internal pressure. The method incorporates ground-induced deformation and evaluates the additional influence of internal pressure on lining behavior. Numerical analyses demonstrate that internal pressure has a significant stabilizing effect on the structural response by reducing ovalization and suppressing nonlinear deformation mechanisms. The results highlight that internal pressure is not a secondary load but a key design parameter that must be integrated into the seismic evaluation of LRC-based hydrogen storage facilities.