Acta Scientiarum Polonorum

Theoretical description and modeling of the behavior of the partially saturated soils requires determination of
their real saturation. The paper presents the method how to describe partial saturation, using the Skempton’s
coefficient B. In the considerations macroscopic description of the fluid consisting of water with air bubbles
filling the pores of soil was implemented. On the basis of the experiments and theoretical background, the effect
of compressibility of the water and air mixture and compressibility of the soil skeleton on the Skempton’s
coefficient B as well as their dependence on back pressure and mean effective stress were shown. The above
is of significant importance in the light of previous studies showing that at some range of saturation the liquefaction
phenomenon could occurred in partially saturated soils as well expanding the threat to engineering
structures. Moreover, based on the results of measurements, an attempt was made to describe the relationship
between the longitudinal wave velocity in the partially saturated medium, the Skempton’s coefficient B and
the degree of saturation.