Laboratory investigation of geogrout inclusion: the influence of the substitution ratio

Laboratory investigations using balloon tests were performed on normally consolidated kaolin samples to investigate their behaviour during and after the balloon expansion. The tests were carried out to simulate a soft soil improvement technique called CPR grouting (acronym for deep radial consolidation). The results allowed estimations of the parameters used in the design method, such as the consolidation potential, and evaluating the generation of pore pressures, injection pressures, post improvement deformation and optimised expanded volume. It was observed that the consolidation potential was extremely dependent on the substitution ratio. The tests satisfactorily reproduced the behaviour of the technique and represent a new device for geotechnical engineers, especially for those concerned with the improvement of soft soils.