ABSTRACT
This paper presents results obtained by using a tensiometer designed in the Soil Mechanics Laboratory of COPPE/UFRJ and several other instruments. This new instrument measures suctions with values of more than 100 kPa. In more typical tensiometers, the cavitation of the system hinders the measurement of suctions with values over 100 kPa. Ridley and Burland (1993) designed a new model of tensiometer to measure suctions of more than 100 kPa. This paper presents an updated model of a tensiometer, using a variation of the equipment used by Ridley and Burland (1993). The updated model worked extremely well and cost little to build. The equipment used allows suctions to be measured relatively quickly and as previously stated is economical to produce (about 300 US$). To date, the range of suctions that can be measured reaches 350 kPa with no difficulty. The tests were carried out in a mini-lysimeter under laboratory conditions. The equipment used included a ceramic stone of 15 m.c.a., pressure sensor, de-aerated water and a special acrylic tube specifically designed for this instrument. The results were compared with two simple automated tensiometer and equivalent tensiometers. In general very comprehensive results were obtained.
