Combined P- and S-Wave Measurements by Seismic Dilatometer Test (SPDMT): A Case History in Bondeno (Emilia Romagna, Italy)

A new seismic dilatometer (SPDMT) has been developed to combine the measurements of the flat dilatometer (DMT) geotechnical parameters with both P- and S- waves velocities. This new SPDMT is composed of the traditional mechanical DMT and four sensors for measuring the body waves velocities placed above the DMT blade. This SPDMT device is presented here, and the test procedure and the interpretation of P- and S-wave measurements are discussed. Results of the application of this new instrument are reported in a test site located in Bondeno (Emilia Romagna, Italy). Here, challenging water table conditions offer the opportunity to evaluate the advantage of a combined measure of the two propagation velocities, together with DMT geotechnical parameters, with the same apparatus for the porosity evaluation and a more calibrated liquefaction assessment.