Thermal properties variations in alluvial sediments of the Po River (Northern Italy)

Abstract

This work aims to highlight the possible influence of grain size, porosity, bulk density, and water content on thermal conductivity and to investigate possible empirical relationships. To achieve this goal, we created an experimental laboratory based on the guarded hot plate method to measure the thermal conductivity of unconsolidated materials. Loose sedimentary deposits were selected from Po Valley (Italy), while the clastic component was separated into standard size ranges and each class tested separately. This allowed us to relate thermal conductivity and grain size while taking into account also other petro-physical parameters. In order to obtain the widest possible granulometric spectrum, investigated samples are in the range from fine pebbles to very fine sand (-3 < φ < +4). These materials were also analysed to identify the present mineral phases. Thermally tests were conducted at different water saturation degrees. The results were processed using statistical techniques and compared with literature data and empirical equations.