Elastic Interpretation of Unsaturated undrained Pressuremeter Tests in clays

The purpose of this study is to solve for pressuremeter the passage of pressure measurements to basic mechanical quantities (E; c; F) with undrained conditions but interpreted in effective stress. This research takes into account the interstitial pressure and the effective stresses for an unsaturated undrained soil. Occluded air is mostly present in natural soils and its compressibility leads to a partial transfer of the total isotropic stresses on the skeleton during undrained stress, which changes for an important way the soil response to undrained stress. This paper presents the theoretical developments and numerical validation in the case of linear elasticity. This is a first step to interpret the pressuremeter test differently and more precisely. For small deformations into finite volume, this study shows the existence of large variations of interstitial pressures related to the variation of the average volume of soil around the pressuremeter.

Ref : Monnet Boutonnier Mahmutovic 2020 - Interprétation théorique de l-essai ressiométrique en condition non drainee V2.pdf