The National Geotechnical Experimentation Site at Opelika, Alabama is underlain by residual silts and sands derived from the weathering of schist and gneiss of the Piedmont Geologic Province. Site characterization by in-situ tests has included anextensive series of cone and piezocone penetrometer soundings supplemented with standard penetration, flat plate dilatometer, pre-bored and full-displacement pressuremeter, and borehole shear.