Proceeding of the 2018 DFI-EFFC International Conference on Deep Foundations and Ground Improvement, Rome, Italy, (DFI, EFFC)
Soil Improvement by Expanding Polyurethane Resins
Andrea Dominijanni, Assistant Professor, Nicoḷ Guarena, PhD Candidate and Mario Manassero, Professor
In recent years, polyurethane resins have frequently been used to improve the mechanical behaviour of soils and to recover foundation settlements after subsidence. Such resins are characterized by the ability to swell when they are exposed to water. As a consequence, in the presence of a confinement, such as that which occurs after injection in the subsoil, the expansive capacity of the resin produces the compaction of the surrounding soil or the propagation of a fracture. In order to supply design tools for this type of intervention, the physico-chemical properties of polyurethane resins are described and the injection modalities, for different types of soil, are illustrated, through basic experimental tests. A simple theoretical approach, which is based on the cavity expansion model in an elastic-plastic medium, is presented in the case of a coarse-grained soil, in order to predict the volume increase of the treated bulb after the injection of the polyurethane resin, when equilibrium is reached with the surrounding soil. Finally, a calculation example is provided, aiming at illustrating the results that can be obtained from the application of this theoretical approach.
|article #3034; publication #1040 (ROME-2018)|