Calibration of the osmotic technique of controlling suction with respect to temperature using a miniature tensiometer

Anh Minh A.M. Tang (1) , Yu-Jun Cui (1) , Li-Xin Qian (2) , Pierre Delage (1) , Wei-Min Ye (2)

1 cermes - Géotechnique
2 Geotechnical Engineering

The osmotic technique was calibrated at various temperatures (20 - 40°C) using a high-capacity tensiometer. The effect of temperature on the calibration curve of the high-capacity tensiometer in the positive range has been found to be insignificant, about 0.03%/°C. The measurement at ambient temperature shows that the suction value is not significantly dependent on the molar mass of poly-ethylene glycol (PEG) nor on the molecular weight cut-off (MWCO) of the semi-permeable cellulose membrane. On the other hand, the matric suction measured in the present work by tensiometer was lower than the total suction found in the literature measured by psychrometer. This shows that the so-called membrane effects must be characterised by not only the crossing of PEG molecules but also other complex phenomena. The calibration at controlled temperatures showed a slight suction decrease by 1%/°C. One possible explanation for this decrease is that increasing temperature decreases the viscosity of PEG solutions, possibly accelerating the PEG molecules crossing. It is also possible that increasing temperature would change the physico-chemical properties of the PEG solutions, resulting in a suction decrease.

Mots clés: calibration; Suction control; osmotic technique; temperature effect; high-capacity tensiometer; poly-ethylene glycol; calibration.

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Anh Minh A.M. Tang, Yu-Jun Cui, Li-Xin Qian, Pierre Delage, Wei-Min Ye. Calibration of the osmotic technique of controlling suction with respect to temperature using a miniature tensiometer. Canadian Geotechnical Journal, 2010, 47, pp.359-365. ⟨hal-00539580⟩