On the measurement of water pressure in soils with high suction tensiometers

Abstract

Past studies on the use of high suction tensiometers for measuring negative pore water pressure have focused on three different aspects, namely, initial saturation of the probe, calibration over both positive and negative pressure ranges, and measurement procedures. Among these three areas, the one focusing on measurement procedures has undeservedly received less attention. Aspects related to measurement conditions during laboratory or field testing are as important as the initial pre-conditioning or calibration of the probe. According to the particular type of measurement, different aspects of the testing procedure have to be considered in order to obtain accurate readings of pore water pressure. This note presents preliminary data to highlight the importance of factors, such as measurement time, soil-probe contact, and material type, when measuring suction by means of high suction tensiometer. © 2009 by ASTM International.