Induced Partial Saturation as mitigation technique against liquefaction: an energetic approach for design tools

Abstract

Induced Partial Saturation (IPS) is considered one of the most innovative and promising countermeasures against liquefaction, due to its low-cost, eco sustainability and its applicability in the urbanized areas, where the need to reduce the risk of liquefaction must be addressed taking into account the integrity of the existing buildings. IPS consists of injecting gas/air into pore water in order to increase the volumetric compressibility of the fluid phase and thus, increasing soil liquefaction resistance. Although the effectiveness of IPS has been confirmed at small and large scale, its use in practical applications is not yet widespread. This can be basically attributed to a lack of design tools. In this paper an energetic approach has been used to build useful design charts, based on the results of in situ (CPT or SPT) tests. The charts allow to choose the degree of saturation to apply in situ to have a desired increase of resistance. A simple application to the case study of Marina District (California) has lastly been shown.