Design of geosynthetics for rigid inclusion ground improvement: A simplified analytical method

The French national project ASIRI+ (2019-2025) is the continuation of the ASIRI project (2005-2012). It aims to provide design recommendations for ground reinforced by rigid inclusions, which, in France, are typically based on the analysis of a unit cell accounting for the behavior of an infinite inclusion group. These so-called “biphasic models” provide all the necessary components for the structural design of rigid inclusions. New topics are introduced in ASIRI+ project, such as horizontal reinforcement of the granular platform using geosynthetics which permits the improvement of the performance of the load transfer platform. In this framework, this paper presents a simplified analytical method that incorporates geogrids into biphasic models. At the level of geosynthetics, which transfers the load to the tops of the inclusions, a relationship coupling the geosynthetic displacement with this load is introduced into the biphasic model equations. The results obtained using this methodology are compared to full-scale tests conducted by the laboratory GEOMAS and the CEREMA of Rouen.