Effect of soil temperature changes on geogrid strains

Temperatures were measured along instrumented geogrids to determine thermal strains and their changes with seasonal temperatures. It was observed that the application of temperature correction to the measured strain values by electrical wire resistance (EWR) strain gauges to compensate for temperature-induced strains is not correct. Because of the effects of soil confinement, the geogrids confined with soil do not undergo thermal expansion or contraction from temperature change if slippage between the soil and geogrid cannot occur. Instead of thermal strains, thermal stress or thermal force will be developed in the geogrids with the magnitude depending on the elastic properties, temperature change, and linear coefficient of thermal expansion. Key words: geogrid, strain gauge, temperature, thermocouple, thermal strain, thermal stress. Les temperatures ont ete mesurees le long de geogrilles instrumentees afin de determiner les deformations thermiques et leurs variations selon les variations saisonnieres des temperatures. Il a ete observe que l'application de la correction pour compenser les deformations induites par la temperature sur les mesures de deformations realisees avec des jauges de deformations par resistance du fil electrique (RFE) n'est pas correcte. En raison des effets de confinement du sol, les geogrilles confinees a l'interieur du sol ne subissent pas d'effets d'expansion ou de contraction thermique lorsque la temperature change s'il n'y a pas de glissement entre le sol et la geogrille. Plutot que des deformations thermiques, des contraintes ou forces thermiques seront developpees dans la geogrille, a des magnitudes dependant des proprietes elastiques, des variations de temperature et du coefficient lineaire d' expansion thermique. Mots-cles : geogrille, jauge de deformation, temperature, thermocouple, deformation thermique, contrainte thermique. [Traduit par la Redaction]
Introduction The first author performed a research graduate thesis in 2003 on the long-term performance of a geogrid-reinforced test embankment constructed in 1986. Vertical and horizontal inclinometers and extensometers, settlement [...]