Influence of air injection on the liquefaction-induced deformation mechanisms beneath shallow foundations

Earthquake-induced liquefaction of soils frequently causes serious damage to structures with shallow foundations. Reducing the degree of saturation of liquefiable soils by air injection is offered as a cost-effective and reliable method of mitigating liquefaction hazards. Nevertheless, very little experimental research is available on the performance of this method. Particularly, the way that air injection influences the deformation mechanisms beneath shallow foundations is not well defined. Gaining a deeper insight into soil displacements during and after air injection can pave the way for developing effective guidelines for the use of this particular technique. For this purpose, a series of dynamic centrifuge tests are presented in this paper. The prevailing deformation mechanisms are identified in a novel way using displacement vector fields. The results indicate that air injection alters the deformation mechanisms that develop underneath and in the ground surrounding a shallow foundation, substantially reducing the average settlements.