Stable inversion of measured V_P and V_S to estimate porosity in fluid-saturated soils

Abstract

Porosity is an important state parameter which controls the response of porous materials under both static and dynamic loading. The possibility of determining porosity from direct inversion of V P and V S , which are routinely measured in geophysical prospecting, is appealing. A methodology has been recently proposed and successfully applied to a number of sites and it is based on the apparent insensitivity of porosity on Poisson ratio of the soil skeleton í SK , which is a priori an unknown quantity. So far, however, the functional dependence of porosity on í SK has only marginally been investigated and doubts arise regarding whether the method is always applicable. This study attempts to investigate thoroughly the stability of the inversion of measured V S and V P to estimate porosity and to assess the degree of well-posedness of the procedure for all the combinations of V P and V S relevant in real soils.La porosité est un paramètre d'état contrôlant la réaction de matières poreuses soumises à des charges à la fois statiques et dynamiques. La possibilité de déterminer la porosité à l'aide de l'inversion directe de V P et V S ,