An energetic interpretation of liquefaction laboratory tets on partially saturated soils

Induced partial saturation (IPS) is considered to be one of the most promising technologies to tackle soil liquefaction risk. The mitigation of the liquefaction susceptibility of loose partially saturated sandy soils is linked to the high volumetric compressibility of the gas or air bubbles entrapped in the continuous water phase. Based on a large amount of experimental data, a new formulation of the potential volumetric strain (εv) of nonsaturated soil is introduced to overcome some experimental inconsistencies linked to the possible dissolution of the air bubbles, that may not be neglected at the laboratory scale if cyclic loads are applied with low frequencies (<1 Hz). Gas dissolution increases the volumetric strains, and if neglected may lead to unconservative estimates of the beneficial effect of desaturation on liquefaction potential. The experimental results of this study also showed that the difference in liquefaction resistance between partially saturated and fully saturated soils depends only on the volumetric component (Ev;liq) of the specific energy spent to attain liquefaction. Such a synthetic state parameter satisfactorily allows predicting the liquefaction resistance curves of partially saturated sands.