ABSTRACT

High-suction tensiometers (Ridley and Burland, 1993) are relatively new devices used for the direct measurement of pore water pressures in soils, including negative pore water pressures below absolute zero. Tensiometers are usually employed under conditions where the air pressure is atmospheric and the matric suction is given by pore water under tensile stress, which is directly measured by the tensiometers. High suction tensiometers can be schematically divided into three parts (Figure 1): a miniature water reservoir, a pressure transducer measuring the water pressure inside the reservoir and a high air entry value porous stone acting as a separation filter between the reservoir on one side and the soil on the other side.