Antonio Galgaro, Philippe Pasquier, Luca Schenato, Matteo Cultrera, Giorgia Dalla Santa, 2018, Soil thermal conductivity from early TRT logs using an active hybrid optic fibre system, Proceedings of the IGSHPA Research Track 2018, Stockholm, Sweden, 18-20/09/2018.,
URL: http://www.cnr.it/prodotto/i/392105

At the Molinella test site in Italy, a monitoring well has been equipped with a hybrid active optical fibre cable down to the depth of 100 m sealed with geothermal grouting. The cored borehole provided a full stratigraphic sequence of unconsolidated alluvial deposits. The cored material has been classified from a geotechnical point of view, and the thermal parameters of the most relevant lithologies have been directly measured. Active heating of the optical fibre cable has been provided by a constant heating power injected through copper wires contained within the cable structure. This way, not only the equivalent thermal conductivity of the entire stratigraphy but also the thermal conductivity at a spatial resolution of 1 m have been obtained. For each investigated layer, the thermal conductivity obtained from the distributed temperature measurements and the ones acquired using direct measurements are interpreted and compared.

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