THE USE OF HYDROPHOBIC AND HYDROPHILIC TENSIOMETERS IN THE MEASUREMENT OF WATER AND NAPL SUCTIONS AND DETERMINATION OF SLRC

Ano:
2011
Palavras chave:
vaporization technique, soil-liquid retention curves, NAPL, multiphase flow.;
Resumo:

This technical note presents some preliminary results obtained with the use of hydrophobic and hydrophilic
tensiometers to measure liquid pressures in three-phase systems (air-NAPL-water). The porous tips of the hydrophobic
tensiometers underwent a surface treatment known as silanization. The silanized tensiometers demonstrated little influence
of the interstitial water in the measured values of NAPL suctions, the contrary occurring in the case of the standard ones.
Due to water preferential wetability, the water tensiometers with standard porous stone tips presented adequate hydrophilic
behavior, measuring water suctions satisfactorily. These tensiometers were also used to determine the soil-liquid retention
curves (SLRC) of an eolian sand by vaporization. Water and diesel were used in the performed tests. The performance of
the vaporization technique was satisfactory, reducing the time required for test accomplishment and presenting repeatable
results. In the case of diesel, due its low vapor pressure and the selective nature of its vaporization process, the use of this
technique was shown to be limited. Sample heating was used to accelerate the vaporization process.