Numerical Simulation Study of Dynamic Response of Salt Cavern Gas Storage under High-Velocity Penetration

Underground salt cavern gas storage serves as a critical piece of energy infrastructure. Damage from impact events can cause irreparable losses, making it essential to establish key dynamic stability indicators for evaluating salt cavern safety under extreme impact loads. To investigate the dynamic response of salt cavern gas storage under high-velocity penetration, the salt rock material was modeled using the Riedel-Hiermaier-Thoma (RHT) constitutive model, and a finite element model of the gas storage structure was developed in ANSYS/LS-DYNA software to analyze the damage effects of a weapon on the salt cavern structure. Numerical simulations were conducted for three scenarios with different overburden thicknesses, monitoring four key parameters: vertical displacement, vertical stress, effective plastic strain, and shear stress. These simulations revealed the failure mechanisms of the cavern roof and surrounding rock under dynamic impact, as well as the variation patterns of the key stability indicators. The results demonstrate that reducing the overburden thickness intensifies the dynamic response of the surrounding rock and expands plastic deformation zones. Displacements of the roof and surrounding rock exhibited a trend of initial increase followed by a decrease. Salt rock in regions of low vertical stress experienced higher shear stresses, increasing its susceptibility to failure. Furthermore, the surrounding rock accumulated greater plastic strain, indicating heightened sensitivity to penetration-induced disturbances.