WAVE PROPAGATION IN SANDY SOIL – AN EXPERIMENTAL AND NUMERICAL MODEL

Existing seismic retrofitting techniques are mainly structural and invasive. Since earthquakes generates from soil and seismic waves propagate through it, alternative solutions for seismic retrofitting have been thought, concerning the insertion of innovative materials in the soil. Polyurethane materials (such as Styrodur or ElastoPor) have already been widely investigated by laboratory testing. In order to evaluate the benefit of their insertion in the soil in terms of PGA decrease and frequency content modification, a little-scale wave propagation study is now introduced. Controlled impact hammer tests adapted to geotechnical uses are performed in a small test wood caisson filled with sand. A FEM model is therefore presented and calibrated on the basis of the comparison with the experimental results. A good agreement between experimental and numerical results allows to anticipate future numerical application of the model to larger studies finalised to the evaluation of seismic amelioration due to polyurethane insertion.