The knowledge of flow and transport phenomena in fractured rocks is very important in hydrogeologic engineering in order to opti - mize clean up and monitoring strategies, to carry out risk assessment and to manage interventions in aquifers. Recently, understanding, characterizing and modeling physical and chemical interactions within fractured aquifers has acquired in - creasing importance, especially with regard to the question of wa - ter resources development and groundwater contamination. Some - times the equivalent porous medium approach fails to reproduce flow and transport patterns in such complex geological formations. Critical emerging issues for fractured aquifers are the validity of the Darcian-type “local cubic law” which assumes a linear relation - ship between flow rate and pressure gradient to accurately describe flow patterns and of the classical advection-dispersion equation to describe the propagation of solute. Most studies of transport through discrete fractures are still based on simpler flow models which has limited the interpretation of solute breakthrough curves. Experimental data obtained under controlled conditions such as in a laboratory allow to increase the understanding of the fundamental physics of fluid flow and solute transport in fractures. In this study hydraulic and tracer tests on artificially created frac - tured rock samples of parallelepiped (0.60×0.40×0.8m) shape have been carried out. The volumes of water passing through different paths across the fractured sample for various hydraulic head differences and break - through curves for saline tracer pulse across different pathways have been measured. The above experiments are aimed at understanding the relations existing between the applied boundary conditions, the geometry of the system and the occurring flow and transport phenomena. The experimental results have shown evidence of non linearity in flow and concentration profiles that cannot be described by conven - tional solute transport models. In fact, the classical advection-dispersion equation -used as a benchmark for comparison in a numerical model- poorly describes the experimental breakthrough curves of the tracer propagation. A comparative analysis of the obtained results has allowed to study the behavior of flow and transport in the investigated medium on the one hand, and to evaluate possible improvements to the experi - mental setup on the other.

The knowledge of flow phenomena in fractured rocks is very important for groundwater resources management in hydrogeological engineering. <br><br> A critical emerging issue for fractured aquifers is the validity of the Darcian-type "local cubic law", which assumes a linear relationship between flow rate and pressure gradient to accurately describe flow patterns. <br><br> Experimental data obtained under controlled conditions such as in a laboratory increase our understanding of the fundamental physics of fracture flow and allow us to investigate the presence of non-linear flow inside fractures that generates a substantial deviation from Darcy's law. <br><br> In this study the presence of non-linear flow in a fractured rock formation has been analyzed at bench scale in laboratory tests. The effects of non-linearity in flow have been investigated by analyzing hydraulic tests on an artificially created fractured rock sample of parallelepiped (0.60 × 0.40 × 0.8 m) shape. <br><br> The volumes of water passing through different paths across the fractured sample for various hydraulic head differences have been measured, and the results of the experiments have been reported as specific flow rate vs. head gradient. The experimental results closely match the Forchheimer equation and describe a strong inertial regime. The results of the test have been interpreted by means of numerical simulations. For each pair of ports, several steady-state simulations have been carried out varying the hydraulic head difference between the inlet and outlet ports. The estimated linear and non-linear Forchheimer coefficients have been correlated to each other and respectively to the tortuosity of the flow paths. A correlation among the linear and non-linear Forchheimer coefficients is evident. Moreover, a tortuosity factor that influences flow dynamics has been determined.

Ricerca , sviluppo,prototipazione, ingegnerizzazione, produzione e commercializzazione di prodotti, processi e servizi innovativi e/o di elevato contenuto scientifico o tecnologico nel campo delle tecnologie geoambientali e geoenergetiche. Studi di fattibilità, progettazione , ingegnerizzazione, di processi innovativi , prototipazione , produzione di impianti pilota e full-scale negli ambiti dell'uso dell'energia geotermica a bassa entalpia, recupero energetico di matrici organiche e gestione sostenibile dei rifiuti.