The classic triaxial compression test is very useful in Soil Mechanics for assessing the parameters of rigidity and strength of the soil under laboratory conditions. Generally, this test consists on applying to the cylindrical sample of soil and all around uniform pressure σ₃ to confine the sample, which is the same as σ₂ and an increasing axial pressure σ₁ to failure, after saturation and consolidation.

In conducting triaxial tests on soil samples it is important to guarantee the total saturation of the samples, to simulate the most adverse moisture condition of the soil that can arise in situ.

There are various methods for assessing the saturation of the samples in the triaxial test. Conventionally, this verification is done at the end of each pressure increment, setting up the Skempton B parameter of pore water pressure.

The main objective of this paper is to show that it is possible to assess the level of saturation by measuring the velocity of seismic compression waves “P” using ceramic piezoelectric transducer (“bender / extend elements” - bending / compression elements). Waves are induced and transmitted through the soil probe during the test. The value of B can be correlated with the velocity of the P wave (V_P). In the search of reference values both B and V_P must be investigated to the condition of complete saturation. In this paper, the conventional classic process of saturation will not be discussed.