A system for field measurement of suction using high capacity tensiometers

This paper presents a new system to measure suction in the field using high capacity tensiometers recently developed through collaboration between Durham University and Wykeham Farrance Limited. The system comprises a borehole probe locator where five tensiometers can be inserted allowing the measurement of suction at different depths. Since the tensiometers are left in place, rather than being used for a single "spot" measurement, suctions can be observed continuously with the aid of a logger and a computer. This enables the measurement of variations of suction due to seasonal changes and the observation of the immediate response to a rainfall event. Two borehole probe locators have been installed at different points in an embankment to measure suction in the fill material. The instrumented embankment was built for research purposes at Nafferton farm, near Newcastle, UK, as part of a cooperative project (BIONICS) investigating the biological and engineering impacts of climate change on slopes. The paper describes the installation and some preliminary observations obtained using the system.