The use of fly ash to alter the engineering properties of artificial “model” clay

This article describes a procedure using fly ash to alter, for similitude purposes, the geotechnical engineering properties of artificial clay used in shaking table physical model studies. The fly ash used in this study acted as a chemically reactive material when mixed with an artificial kaolinite-bentonite model clay. When added to the model clay, the fly ash stiffened the soil (increased shear wave velocity) while lowering the soil’s undrained shear strength. To avoid increasing the strength of the model soil, the fly ash-clay mixture had to be thoroughly remolded at least several days after initial mixing. The article discusses an application of this model soil preparation procedure for a 1-g shaking table study of seismic soil-pile-superstructure interaction in a soft marine clay.