<p>The promotion of Energy Geostructures (EGs) is strongly related to the use of renewable and clean energy resources for the heating and cooling of buildings. They couple the structural role of geostructures with the exploitation of Low Enthalpy Geothermal Energy (LEGE). During their operation, EGs are continuously subjected to thermal variations, due to the heat exchange between the soil and heat transfer fluid circulating in the pipes inserted in the structure. This can lead to an impact on the mechanical response of the structure, and the role of the soil-structure interface takes on relevance in this operation. Nevertheless, experimental results deriving from the literature on the Thermo-Mechanical (TM) soil-structure interface behavior suggest that the effect of temperature on the shear resistance is quite limited, in the case of interaction with a building material such as concrete, especially for coarse-grained soils. The case of fine-grained soils is more complex: some studies suggest an enhancement of the interface shear strength, showing an increase of adhesion or a slight increase in friction angle at the interface during heating; while other studies show no significant variations of the interface behavior with thermal cycles. Such differences are likely due to the multitude of experimental configurations, development protocols, and composition of the samples used during tests. With the aim of better understanding this controversial framework on the interface behavior, a modified device for direct shear tests was developed at the Laboratory of Geotechnical Engineering of the University of Perugia: starting from the conventional direct shear apparatus, this has been equipped with a heating cement plate, where a thermal resistance and a temperature probe for continuous temperature control have been integrated. The first tests on silty sand reconstituted samples have shown that the thermal effects at the interface are limited to a decrease in shear strength of less than 3%.</p>

Surface soil moisture is a key hydrologic state variable that greatly influences the global environment and human society. Its significant decrease in the Mediterranean region, registered since the 1950s, and expected to continue in the next century, threatens soil health and crops. Microwave remote sensing techniques are becoming a key tool for the implementation of climate-smart agriculture, as a means for surface soil moisture retrieval that exploits the correlation between liquid water and the dielectric properties of soil. In this study, a workflow in Google Earth Engine was developed to estimate surface soil moisture in the agricultural fields of the Marche region (Italy) through Synthetic Aperture Radar data. Firstly, agricultural areas were extracted with both Sentinel-2 optical and Sentinel-1 radar satellites, investigating the use of Dual-Polarimetric Entropy-Alpha decomposition's bands to improve the accuracy of radar data classification. The results show that Entropy and Alpha bands improve the kappa index obtained from the radar data only by 4% (K = 0.818), exceeding optical accuracy in urban and water areas. However, they still did not allow to reach the overall optical accuracy (K = 0.927). The best classification results are reached with the total dataset (K = 0.949). Subsequently, Water Cloud and Tu Wien models were implemented on the crop areas using calibration parameters derived from literature, to test if an acceptable accuracy is reached without in situ observation. While the first model’s accuracy was inadequate (RMSD = 12.3), the extraction of surface soil moisture using Tu Wien change detection method was found to have acceptable accuracy (RMSD = 9.4).