Search

Nowadays, groundwater is the most important resource on our planet. However, due to population growth, urbanisation, and climate change, this resource is often overexploited or contaminated. In this context, carbonate aquifers provide drinking water to approximately 25% of the global population. Due to aquifers heterogeneities and anisotropic fracture systems, they can be affected by potential contamination and their optimal exploitation represents a challenge aspect. In this particular scenario, carbonate mountain aquifers encompass valuable groundwater resources due to their high recharge rates and excellent water quality; therefore, the understanding of their hydrogeological characteristics are vital for aquifers protection and water management. A valid solution to explore water movement within such aquifers and to quantify the groundwater amount can be offered using artificial tracers. At the same time, the geomechanical surveys can deep the knowledge on fracture density and orientation, providing valuable insights about fracture connection and conductivity. This study combines the advantages of six artificial tracer tests performed in four deep wells (260-500 m b.g.l.) and a geomechanical survey used, among other, to estimate hydraulic conductivity of a mountainous carbonate aquifer located in Central Italy. The results obtained by different methods highlighted the presence of multiple layers with higher conductivity values, able to sustain the groundwater flow without significant piezometric level drawdown during water pumping operations. This approach provides an effective support to the water management company operating. [ABSTRACT FROM AUTHOR]

The paper presents some approximate solutions for the time-dependent analysis of composite steel-concrete beams with flexible shear connectors. These permit evaluating the migration of the stresses from the concrete slab to the steel beam and the increment of the deflections, which occur gradually with time as a result of creep and shrinkage of the concrete part. The mathematical formulation of this problem, which involves a coupled system of three equations, with two being integral-differential-type equations, is reduced to a system of ordinary differential equations by applying the algebraic methods (age-adjusted-effective-modulus, effective-modulus, and mean-stress methods). The simplifications introduced by these methods permit obtaining solutions in closed form, which can be useful for practical applications. The accuracy of the numerical results is successively estimated by comparing these values with those of the exact numerical solution, obtained by employing the numerical algorithm proposed elsewhere using the numerical step-by-step procedures of the general method.