Experimental results on an energy pile within a sheet pile wall in Napoli

Abstract

Energy geo-structures are renewable energy solutions with a double role of structural support and heat exchangers. Some installations are recorded worldwide, but only limited information is available regarding the impact of thermal processes on the structural and geotechnical performance of energy geo-structures. A proper experimental campaign was conducted within the underground railway construction site of Piazza Municipio in Napoli (South Italy). An energy sheet pile wall was built and equipped with fibre optic sensors system allowing the evaluation of strains and temperature distributions along the piles, during geothermal processes. Results on a single energy pile and measurements undertaken during the field experiment are presented highlighting the effects of temperature variations on the mechanical behaviour of the soil-structure system. From temperature measurements, it can be observed that, due to the excavation, there was a strong influence of the outside air temperature. Despite measurement uncertainties and some data gaps resulting from cut cables, the data presented makes a contribution to improving the available monitored case studies in the literature on energy structures.