Liquefaction characteristics of desaturated coral sand foundation with upper building

Liquefaction of coral sand foundations under explosive loads poses significant risks to the safety of upper buildings. In this paper, a coral sand foundation and upper buildings are taken as the research objects, and dynamic tests of buildings in coral sand foundations are conducted via the electrolytic desaturation method under the action of multiple charge packages with delay. The experimental results show that the delayed detonation of multiple charges produces multiple loading effects, the excess pore pressure ratio rapidly decays exponentially with increasing proportional distance. After electrolytic desaturation reinforcement with 700 min and a constant current of 2 A, the degree of saturation of the coral sand foundation decreases from 100 to 85%, and the maximum reduction of the excess pore pressure ratio in the foundation is approximately 33%. The effect of electrolytic desaturation on the acceleration response of the structure is relatively small, but the vertical settlement of the structure in saturated foundation is reduced by approximately 30% compared with that in desaturated foundation. The numerical results show that the empirical prediction formula for multi charge explosion liquefaction can better reflect the trend of site liquefaction with increasing distance. For saturated and loose coral sand sites with a small thickness of the soil layer above the charge, the Studer's empirical model is suitable for prediction.