ISSN: 1945-7545
CODEN: GTJODJ
Published Online: 6 July 2010
Page Count: 6

Principle and Prototype Testing of a New Matric Suction Sensor

Dunmola, Adedeji
Dept. of Civil and Environmental Engineering, Carleton Univ., Ottawa, ON

Simms, Paul
Dept. of Civil and Environmental Engineering, Carleton Univ., Ottawa, ON

Padilla, Manuel
GCTS Testing Systems, Tempe, AZ

(Received 26 September 2008; accepted 8 June 2010)

Abstract

A new principle for matric suction measurement is proposed, based upon strain measurement of a contiguous porous material of high air-entry value (AEV). In theory, this allows for the measurement of matric suction without the associated errors due to cavitation or hysteresis for suctions below the AEV. Results from testing a prototype sensor made from a deformable porous material with a high AEV (S=0.85 at 5 MPa) are presented. Deformation of the prototype was determined by means of attached electrical resistivity strain gauges. Matric suction is then inferred from the strain measurements using poroelasticity theory. Tests performed in a drying artificial silt show that matric suction values inferred using the prototype sensor showed reasonable agreement with corresponding values obtained using a tensiometer, a psychrometer, and with suctions established using axis-translation. Mean absolute errors of matric suction measurement were 8, 16, and 100 kPa for ranges of 0–150, 50–300, and 300–1200 kPa, respectively.

Keywords:
poroelasticity, matric suction, poroelastic sensor, measurement

Paper ID: GTJ102142
DOI: 10.1520/GTJ102142
ASTM International is a member of CrossRef.