An experimental study was carried out to evaluate the influence of silt content on cone penetration measurements and its implication for soil classification. The investigation includes twenty-seven peizocone tests in saturated salty sand samples, which had been prepared in a big rigid thick walled steel cylinder-testing chamber. The samples were prepared with several different silt contents ranging from 0 to 50 percent and were consolidated at three-overburden effective stresses including 100, 200 and 300 kPa. This study showed that, the amount of silt content in sand is an important parameter affecting CPT results. As the silt content increases, the cone tip resistance decreases. The recorded excess pore water pressure during sounding was increased with increasing silt content. It is also concluded that friction ratio, in general, increases with increasing silt content. The method presented by Robertson and Wride [25] and Olsen [17] to evaluate soil classification are also verified.

Keywords: Cone tip resistance, Silty sand, Excess pore Water pressure, Friction ratio, Soil Classification, Cone penetration test