20 research outputs found
Energy retrofitting of existing tunnels - from conceptualization to full-scale implementation
No full textL'abstract è presente nell'allegato / the abstract is in the attachmen
Sfruttamento geotermico di gallerie esistenti a fini di anti-icing stradale
No full textConsiderando sia le emissioni di dirette che quelle indirette, il settore delle costruzioni contribuisce a circa il 18% delle emissioni globali di CO2eq. Per raggoiungere l'obiettivo fissato dall'accordo di Parigi, le geostrutture energetiche possono rappresentare una soluzione per rendere il settore civile più eco-sostenibile in quanto in grado di produrre energia termica rinnovabile ed a basso impatto ambientale. Questo contributo descriverà i risultati di alcune analisi numeriche preliminari condotte per valutare l'attuabilità di un sistema di anti-icing geotermico che approvvigionerà calore da una galleria esistente strumentata per lo scambio di calore durante i lavori di rinnovo strutturale della stessa
A Simple Parametric Numerical Model to Assist the Design of Repair Works and Maintenance of Tunnels
No full textTunnels are resilient infrastructures whose service life is generally much higher than the designed nominal one, thus increasing the number of existing tunnels still in operation with an average service life of more than 50 years. From a more Italian perspective, Italy’s complex morphology has made it necessary to excavate a considerable number of tunnels to develop the nowadays railway and motorway traffic lines. However, recent cases of tunnel lining local collapses have highlighted that some existing Italian tunnels have almost reached the end of their service life, revealing their maintenance, refurbishment and/or upgrading works to be an urgent need. Taking advantage of the tunnel refurbishment plan ongoing in Italy, the aim of this study is to support the design of temporary maintenance works by means of simple numerical modelling. In such a way it is possible to consider fundamental geotechnical parameters that can play a key role in the effectiveness and in the applicability of the studied maintenance solutions. The attention is here devoted to interventions with suspended steel ribs to prevent local instabilities of the aged concrete
Seizing the opportunity of energy retrofitting of existing tunnels
No full textEnergy tunnels have emerged as systems that can contribute to the production of clean, renewable thermal energy. Nevertheless, so far applications have been related almost exclusively to new tunnelling projects. Accordingly, no systematic methodologies for the heat exchange instrumentation of existing tunnels have been proposed up until now. Starting from the valuable experience gained from different energy tunnel testbeds worldwide, this paper proposes two approaches that would allow the thermal activation of the existing heritage of tunnels. Different solutions are conceived for both approaches to fit various existing tunnel decay contexts and diverse levels of refurbishment necessity. These are illustrated, outlining characteristics and advantages, describing expected installation details and issues and analysing the possibility of real implementations. The geothermal potential of such solutions is assessed through thermo-hydraulic numerical modelling. Finally, with the aim of investigating their economic attractiveness and profitability, a brief economic analysis is drawn up, considering the geothermal energy produced and the costs involved in installing and running the systems
A solar-collecting system for tunnel thermal storage
No full textDespite being resilient geostructures, a non-negligible amount of tunnels worldwide are approaching the end of their service life. This is mainly evident in Italy due to the agedness of most of the underground built environment. To address this issue, a plan to renovate existing motorway tunnels is underway to extend their serviceability. In this framework, a novel energy tunnel based anti-icing solar-collecting system is being implemented on a full scale in a motorway tunnel undergoing renovation. This envisages a geothermal serpentine embedded in the rehabilitated lining connected to other heat exchanger piping placed within the motorway pavement. Working in free-cooling mode, the system can take advantage of the thermal inertia of the ground behind the lining to store the solar heat collected through the motorway pavement, acting as a solar collector. The aim is to use this heat for anti-icing operations during the harshest periods of winter seasons.
This paper will illustrate the laboratory testing and numerical modelling needed to preliminarily assess the
functionality of the energy tunnel based anti-icing solar-collecting system
Numerical modelling of existing tunnels subjected to time dependent threats
No full textDealing with time-dependent phenomena during tunnel excavation and management is a complex topic that engineers and geologists need to face worldwide. Threats to tunnel stability are posed by the swelling/creep behaviour of geomaterials. These phenomena occur during the construction of the tunnel but can evolve for a long period after tunnel operation and can jeopardize the tunnel integrity with time. Although the topic of time-dependent behaviour has been repeatedly addressed in the literature, less attention has been paid to methodologies to deal with it during the serviceability of tunnels. Therefore, appropriate and reliable methods are needed to analyse and predict tunnel behaviour during their service life and/or refurbishment processes. This paper will focus on existing tunnels subjected to the time-dependent behaviour of the surrounding ground to identify the methodological approach for designing maintenance works and/or managing the associated risks. Examples from the Authors' experience are used to support the discussion
Anti-icing using the heat recovered in the Lagoscuro tunnel
No full textIn the context of promoting local energy sources with low environmental impact, energy geostructures are more and more being explored. This paper will describe an example of a technological system able to achieve the anti-icing of the motorway pavement through the exploitation of heat from the adjacent tunnel. Taking advantage of the current motorway refurbishment plan fostered by Autostrade per l'Italia (ASPI) and the activities planned for the Lagoscuro tunnel, located along the A26 motorway in the Genova province, the opportunity for geothermal energy exploitation is being tested in a full-scale prototype. The details of the experimental site setup will be revealed together with the characteristics of the pavement anti-icing solution
Opposing effects of 25-hydroxy- and 1α,25-dihydroxy-vitamin D3 on pro-cachectic cytokine- and cancer conditioned medium-induced atrophy in C2C12 myotubes
No full textCholecalciferol (vitamin D3) has a direct protective activity against interleukin 6-induced atrophy in C2C12 myotubes
No full textWe previously determined that different vitamin D metabolites can have opposite effects on C2C12 myotubes, depending on the sites of hydroxylation or doses. Specifically, 25(OH)D3 (25VD) has an anti-atrophic activity, 1,25(OH)2D3 induces atrophy, and 24,25(OH)2D3 is anti-atrophic at low concentrations and atrophic at high concentrations. This study aimed to clarify whether cholecalciferol (VD3) too, the non-hydroxylated upstream metabolite, has a direct effect on muscle cells. Assessing the effects of VD3 treatment on mouse C2C12 skeletal muscle myotubes undergoing atrophy induced by interleukin 6 (IL6), we demonstrated that VD3 has a protective action, preserving C2C12 myotubes size, likely through promoting the differentiation and fusion of residual myoblasts and by modulating the IL6-induced autophagic flux. The lack, in C2C12 myotubes, of the hydroxylase transforming VD3 in the anti-atrophic 25VD metabolite suggests that VD3 may have a direct biological activity on the skeletal muscle. Furthermore, we found that the protective action of VD3 depended on VDR, implying that VD3 too might bind to and activate VDR. However, despite the formation of VDR-RXR heterodimers, VD3 effects do not depend on RXR activity. In conclusion, VD3, in addition to its best-known metabolites, may directly impact on skeletal muscle homeostasis
