Correlations between p-wave velocity and SPT-N for saturated and unsaturated alluvial clays using dimensional analysis

The aim of this research is to establish practical and robust correlations between dilatational wave velocities (p -wave velocities, Vp) and the Standard Penetration Test blow count (SPT-N). Very low levels of correlation are recorded with the conventional single variable approaches, in consequence, a multivariable study is needed for higher precision. A dimensional analysis was conducted including other soil parameters that condition this physical phenomenon, such as the void ratio (e), the degree of saturation (Sr), the effective overburden pressure (sigma ' v), and the particle density (gamma s), for greater precision with Vp and SPT-N correlations. Over 100 seismic and SPT tests were performed around the coastal city of Juchit ' an de Zaragoza (Oaxaca), Mexico, to gather information for this research. As a result, two dimensionless indexes -DSIu (Undrained Dilatational Stiffness Index) and MDSIu (Modified Undrained Dilatational Stiffness Index)-yielded two alternative expressions between both indexes and Vp. In this way, a strong relationship between Vp and SPT-N was obtained with an adjusted coefficient of determination R2 value of 0.93.