CPT calibration in centrifuge: Effect of partial saturation on cone resistance

When dealing with unsaturated soil conditions, the influence of matric suction on cone tip resistance of the soil above the ground water table is typically neglected in engineering practice, with consequent possible misinterpretation of soil features. In the last decades, various researchers have investigated the influence of suction on cone resistance for sands, whilst still little is known for silty materials, whose contribution can be significant and extended for many meters above the groundwater table. Such issue is especially relevant for compacted earth structures, like river embankments, typically made of a heterogeneous mixture of intermediate soils. With the aim of providing a contribution and stimulating its correct implementation into geotechnical practice, a set of miniature piezocone tests have been carried out in a centrifuge on both saturated and partially saturated silty sand models. The interpretation of CPT results is discussed, highlighting the effect of partial saturation on cone tip resistance.