Indirect Measurement of Suction

Abstract

This paper reports on indirect soil suction measurement methods. Indirect suction measurement techniques measure the moisture equilibrium condition of the soil instead of suction. The moisture equilibrium condition of the soil can be determined by primary means as in vapor pressure, secondary means as through another porous medium or tertiary means as in measuring other physical properties of the porous medium that indicates its moisture equilibrium condition. Indirect suction measurement techniques employing primary means include thermocouple psychrometers, transistor psychrometer and chilled-mirror psychrometer. Indirect suction measurement techniques employing secondary means includes the filter paper method and indirect suction measurement techniques employing tertiary means include thermal conductivity sensors and electrical conductivity sensors. These techniques have been widely used in engineering practice and in research laboratories. However, each of these techniques has its own limitations and capabilities, and active research into improving these techniques is ongoing in universities, research laboratories, and private sector. This paper outlines working principles, calibration, measurement, and application areas of these methods based on recent literature and practice.

Filter Paper Method for the Determination of the Soil Water Retention Curve

“…The greater speed of the filter paper method was emphasized in other studies (Chandler and Gutierrez, 1986;Bulut and Leong, 2008;Lucas et al, 2011).…”

“…42 and Schleicher & Schuell No. 589-WH (Leong et al, 2002;Bulut and Wray, 2005;Bulut and Leong, 2008). Among all known methods for measuring soil water potential, the filter paper technique is the only method to determine both the total soil water potential and matric potential (Bulut and Wray, 2005;Bulut and Leong, 2008;Beddoe et al, 2010).…”

Development of a MEMS Sensor System for <em>In-Situ</em> Monitoring of the Engineered Barrier in a Geological Disposal Facility

“…There exist several different methods to measure the relative humidity of the water vapour in equilibrium with the bentonite blocks. Besides the installation of a traditional RH sensor at the point of interest (which would disturb the sample and be too large as to be incorporated), it is also possible to measure the RH using a Chilled-Mirror Psychrometer [12]. The psychrometer used in this experimental programme is a product of Decagon Devices, Inc. and is known as a WP4 Dew Point Potentiameter.…”

Measurement of soil suction using moist filter paper

“…However, despite being standardized in ASTM D5298-10 [1], the experimental procedures are still controversial and research is being performed to better understand the technique. Substantial contributions to the filter paper suction measurement technique have been made by Al-Khafaf and Hanks [2], Houston et al [3], Bulut et al [4], Likos and Lu [5], Leong et al [6], Marinho and Oliveira [7], Bicalho et al [8], Bulut and Leong [9], Haghighi et al [10] and Marinho and da Silva Gomes [11].…”