Experimental comparison of air entrapment capacity in sandy soils for liquefaction mitigation: Evaluating air injection method efficiency in soil desaturation

Abstract

The air injection method has been identified as a promising liquefaction mitigation technique to enhance the liquefaction resistance of sand. This innovative approach involves reducing the saturation degree of sand by injecting air, ultimately mitigating the generation of excess pore pressure during seismic events. This paper thoroughly investigates the potential of sandy soil to entrap air bubbles to reduce saturation degree. Fujian silica sand and the South China Sea calcareous sand, with varying gradation curves, were selected to evaluate the influence of key parameters such as uniformity coefficient, void ratio, and relative density on the air entrapment capacity. Box model experiments utilizing the air injection method were performed to evaluate the air entrapment capacity of sands. The findings reveal that the physical properties of sand can influence both the air distribution pattern and the air entrapment capacity. Finally, two additional tests were performed on transparent fused quartz sand to further examine the air injection process. The ability to observe air bubble distribution within the pore structure of the transparent sand enabled a qualitative comparison, facilitating the analysis of results obtained from experiments on natural sand samples.