TARANTINO A.

CPT sounding initially passes through the vadose zone, that is the zone above the phreatic surface where pore-water pressure is negative and degree of saturation is usually lower than unity. Negative pore-water pressure (suction) significantly affects tip resistance and sleeve friction and lack of knowledge of soil suction in this zone makes...

The High Capacity Tensiometer (HCT) is a soil sensor that can measure large negative pore-water pressures, i.e. in excess of −1 MPa, and is a key instrument for monitoring ground-atmosphere interactions. The design of HCTs has not changed since the first prototype was proposed in the 1990s and still includes three main components, namely a high...

Tensiometers are increasingly used in geotechnical engineering to monitor pore-water tension in the field and to study the hydro-mechanical behaviour of unsaturated soils in the laboratory. Early tensiometers exhibited a relatively small measuring range, typically limited to a tension of 0·1 MPa, due to the breakdown of water tension inside the...

The in-situ monitoring of soil suction and water content is important for a range of applications from civil engineering (e.g. estimation of groundwater infiltration) to agriculture (e.g. optimization of irrigation). The efficiency of field monitoring systems has recently improved thanks to the development of sensors that continuously record...

High capacity tensiometers (HCTs) are sensors capable of directly measuring tensile pore water pressure (suction) in soils. HCTs are typically composed of a casing that encapsulates a high air entry value ceramic filter, a water reservoir and a pressure sensing element. Since the creation of the first HCT by Ridley and Burland in 1993 at...