Intergranular void ratio - Steady state strength relations for silty sands

Monotonic undrained shear strength (S-us) data for triaxial compression for three silty sands prepared by mixing non-plastic fines with a particular host sand are presented. Results indicate that intergranular void ratio, e(s), plays an important role on S-us. At the same e(s), (less than the maximum void ratio of the host sand e(max,HS)), the silty sand and the host sand show similar S-us. The strength is independent of initial confining stress. When e(s) of the silty sand is in the vicinity of, or larger than the e(max,HS) the S-us of the silty sand is very low and it is dependent on the initial effective confining stress. This effect must be taken into consideration in analyzing seismic stability of sites consisting of silty sands.