INTERFEROMETRIA RADAR E MODELLAZIONE FDEM PER LO STUDIO DI FRANE IN ROCCIA: UN ESEMPIO DI APPLICAZIONE

Nella presente nota verrà illustrato un esempio di applicazione della tecnica interferometrica radar da terra (GBInSAR) e di modelli numerici avanzati di tipo combinato elementi finiti-elementi distinti (FDEM) per lo studio del cinematismo e della propagazione di una frana in roccia nell'Appennino umbro (Torgiovannetto di Assisi -PG). Con riferimento al caso di studio saranno mostrati i risultati del monitoraggio radar che hanno consentito di delimitare l'area interessata dagli spostamenti e di individuare nel cuneo in frana spostamenti differenziali non noti precedentemente. Al contempo saranno mostrati i risultati dell'analisi di scenario effettuata tramite i modelli numerici FDEM che, opportunamente tarati, hanno consentito di ricostruire i meccanismi di innesco, la possibile evoluzione e la distanza di propagazione dei fenomeni oggetto di studi

Early warning monitoring of natural and engineered slopes with Ground-Based Synthetic Aperture Radar

The first application of ground-based interferometric synthetic-aperture radar (GBInSAR) for slope monitoring dates back 13 years. Today, GBInSAR is used internationally as a leading-edge tool for near-real-time monitoring of surface slope movements in landslides and open pit mines. The success of the technology relies mainly on its ability to measure slope movements rapidly with sub- millimetric accuracy over wide areas and in almost any weather conditions. In recent years, GBInSAR has experienced significant improvements, due to the development of more advanced radar techniques in terms of both data processing and sensor performance. These improvements have led to widespread diffusion of the technology for early warning monitoring of slopes in both civil and mining applications. The main technical features of modern SAR technology for slope monitoring are discussed in this paper. A comparative analysis with other monitoring technologies is also presented along with some recent examples of successful slope monitorin

MODELIRANJE KONTINUITETA I DISKONTINUITETA U TUNELSKOM INŽENJERSTVU

The paper discusses continuum and discontinuum modelling in tunnel engineering. A brief review of fundamentals is presented in connection with the use of closeg - form solutions and computer based numerical methods. a few remarks are derivedon the choice of either continuum or discontinuum modelling of rock mass behaviour at the design analysis stage. Consideration is given to the validation of discontinuum modelling in connection with rock mass classification methods and expected tunnel response to excavation. A case study of a TBM tunnel (4.75 m) in quartzitic micaschists is discussed in detail by paying attention to a comparison of modelling methods - including continuum and discontinuum modelling - applied at a fault zone.U članku je raspravljeno modeliranje kontinuiteta i diskontinuiteta u tuelskom inženjerstvu. Sažeto su opisane osnove zajedno s uporabom matematičkih rješenja i računalnih numeričkih metoda. Raspravljen je izbor modela kontinuuma i diskontinuuma stjenske mase u odnosu na analizu konstrukcije podgrađivanja. U obzir je uzeto potvrđivanje modela diskontinuiteta povezanog s metodama klasifikacije stjenskih masa i očekivane reakcije tunela pri iskopu. U detaljima je raspravljen prmjer studije TBM tunela (promjera 4,75 m) u kvarcitičnim mikašistima s posebnom pozornosti na uspoređivanje metoda modeliranja - uključujući modeliranje kontinuuma i diskontinuuma - uporabljenih u rasjednoj zoni

Tunnels in swelling ground: simulation of 3D stress paths by triaxial laboratory testing

The research is devoted to study the swelling behaviour in tunnels. A new triaxial testing procedure is developed, which is able to quantify the swelling behaviour of soft rocks and stiff soils. The Caneva Clay is tested both by conventional oedometer swelling tests and by the new triaxial test. The swelling parameters of the clay are quantified for predictive analyses of the swelling behaviour at the tunnel scale

Development and testing of a novel geothermal wall system

Shallow geothermal energy systems have the potential to contribute to the decarbonization of heating and cooling demands of buildings. These systems typically present drawbacks as high initial investments and occupancy of wide areas. In this study, a novel energy wall system is proposed to overcome the limitations of conventional geothermal applications in urban areas. The system is characterized by ease of installation, low initial costs and applicability to existing buildings undergoing energy retrofitting. The paper illustrates the implementation of the prototype of such a system to an existing structure in Torino (Italy). An overview of the components is given together with the interpretation of an illustrative test carried out in heating mode. The data from both heating and cooling experimental campaigns allow us to highlight the potential of the proposed technology. The results suggest that an average thermal power of about 17 W per unit area can be exchanged with the ground in heating mode, while an average of 68 W per unit area is exchanged in cooling operations. The negligible impact on the stress–strain state of the wall and the surrounding soil thermal and hygrometric regime is also testified by the results collected. These aspects are associated with a reduced probability of interferences with other installations in highly urbanized areas, easiness of installation and affordable cost

rOGER: A method for determining the geothermal potential in urban areas

Shallow geothermal energy is increasingly adopted for heating and cooling purposes because of the short payback time of initial installation investments. As a result, a relevant concentration of Ground Heat Exchangers is being experienced in urban areas. Planning issues thus arise to manage interferences and optimize the use of underground heat resources without depletion, harm to the environment nor efficiency losses on heat pumps or plant oversizing. This study provides a rational approach to optimise geothermal resources based on the use of Geographic Information Systems and transient 3D Thermo-Hydro numerical models. An optimised semianalytical formula for the assessment of Borehole Heat Exchangers geothermal potential in hydrodynamic conditions is developed through a parametric numerical study. The long-term performances of BHE subjected to groundwater velocity in the range of 0 to 1 m/day were analysed with multiple aquifer thermal parameters. This analytical expression allows a fast and accurate assessment of the potential even in large areas without leading to excessively conservative evaluations. This may serve designers in the preliminary sizing of installations and city planners in the development of appropriate policies for the promotion and management of shallow geothermal resources. An example of the application to the central district of the city of Turin (Italy) is also shown

Monitoring geotechnical structures by ground based radar interferometry

This paper describes two novel remote sensing techniques based on radar sensors, respectively the Synthetic Aperture Radar (SAR) and the Real Aperture Radar (RAR), and some applications to relevant geotechnical problems with the aim to demonstrate the outcomes these types of sensors can provide. The case studies here described show how the SAR technique can provide useful information to interpret landslides’ kinematics and how the RAR can be used to monitor dam displacements and tunnels’ convergences

MODELIRANJE KONTINUITETA I DISKONTINUITETA U TUNELSKOM INŽENJERSTVU

The paper discusses continuum and discontinuum modelling in tunnel engineering. A brief review of fundamentals is presented in connection with the use of closeg - form solutions and computer based numerical methods. a few remarks are derivedon the choice of either continuum or discontinuum modelling of rock mass behaviour at the design analysis stage. Consideration is given to the validation of discontinuum modelling in connection with rock mass classification methods and expected tunnel response to excavation. A case study of a TBM tunnel (4.75 m) in quartzitic micaschists is discussed in detail by paying attention to a comparison of modelling methods - including continuum and discontinuum modelling - applied at a fault zone.U članku je raspravljeno modeliranje kontinuiteta i diskontinuiteta u tuelskom inženjerstvu. Sažeto su opisane osnove zajedno s uporabom matematičkih rješenja i računalnih numeričkih metoda. Raspravljen je izbor modela kontinuuma i diskontinuuma stjenske mase u odnosu na analizu konstrukcije podgrađivanja. U obzir je uzeto potvrđivanje modela diskontinuiteta povezanog s metodama klasifikacije stjenskih masa i očekivane reakcije tunela pri iskopu. U detaljima je raspravljen prmjer studije TBM tunela (promjera 4,75 m) u kvarcitičnim mikašistima s posebnom pozornosti na uspoređivanje metoda modeliranja - uključujući modeliranje kontinuuma i diskontinuuma - uporabljenih u rasjednoj zoni