Interpretation of Seismic Piezocone Results for the Estimation of Hydraulic Conductivity in Clays

Seismic piezocone penetration tests with dissipation phases provide sufficient data for outlining the geostratigraphy, soil strength, stiffness, and flow characteristics in fine-grained soils. The dissipation of excess pore water pressures with time can be monitored at regular intervals (e.g., at 1-m rod breaks) and provides information on the coefficient of consolidation (ch). Monotonic and/or dilatory responses of Δu decay can be accommodated. The shear wave velocity (Vs) provides a measure of the small-strain stiffness (G0), or surrogate evaluation of the constrained modulus (D′). A sampling of data from ten clay sites was used to assess the derived magnitude of hydraulic conductivity, as determined from k = chγw/D′.