Abstract: Under explosion loading, saturated calcareous sand foundations are susceptible to vibrational liquefaction, posing significant catastrophic risks to superstructures. To investigate this, dynamic model tests were conducted on calcareous sand foundations under explosive conditions, comparing the dynamic liquefaction behaviors of both saturated and electrolytically desaturated calcareous sand foundations. The study reveals that for saturated calcareous sand foundations, the blast-induced liquefaction pattern is intricately linked to explosion vibrations, scaled burial depth, and the evolution of pore water pressure within the soil. The dynamic response of the superstructure is pronounced, with acceleration responses peaking at the bottom and diminishing towards the top. The strain in the superstructure columns is greatest at their bases, and the maximum displacement of the superstructure occurs in the y-direction. Following 300 minutes of electrolytic desaturation treatment with a constant current of 1 A, the saturation level of the saturated coral sand foundation decreases from 100% to 89.5%. Under explosion vibrations, the desaturated coral sand foundation exhibits a roughly 10% reduction in maximum excess pore pressure and an approximately 25% decrease in structural displacement, while the acceleration response of the superstructure remains relatively consistent. These findings demonstrate that electrolytic desaturation measures effectively mitigate the vibration liquefaction of saturated calcareous sand, offering crucial insights for ensuring the safety and stability of geotechnical engineering projects on islands and reefs.

Key words: blast-induced liquefaction, calcareous sand, foundation, saturation reduction, structural dynamic response