The fracturing state of rocks is a fundamental control on their hydro-mechanical properties. It can be quantified in the laboratory by non-destructive geophysical techniques that are hardly applicable in situ, where biased mapping and statistical sampling strategies are usually exploited. We explore the suitabilty of infrared thermography (IRT) to develop a quantitative, physics-based approach to predict rock fracturing starting from laboratory scales and conditions. To this aim, we performed an experimental study on the cooling behaviour of pre-fractured gneiss and mica schist samples, whose 3D fracture networks were reconstructed using Micro-CT and quantified by unbiased fracture abundance measures. We carried out cooling experiments in both controlled (laboratory) and natural (outdoor) environmental conditions and monitored temperature with a thermal camera. We extracted multi-temporal thermograms to reconstruct the spatial patterns and time histories of temperature during cooling. Their synthetic description show statistically significant correlations with fracture abundance measures. More intensely fractured rocks cool at faster rates and outdoor experiments show that differences in thermal response can be detected even in natural environmental conditions. 3D FEM models reproducing laboratory experiments outline the fundamental control of fracture pattern and convective boundary conditions on cooling dynamics. Based on a lumped capacitance approach, we provided a synthetic description of cooling curves in terms of a Curve Shape Parameter, independent on absolute thermal boundary conditions and lithology. This provides a starting point toward the development of a quantitative methodology for the contactless in situ assessment of rock mass fracturing.

Franzosi, F., Casiraghi, S., Colombo, R., Crippa, C., Agliardi, F. (2023). Quantitative Evaluation of the Fracturing State of Crystalline Rocks Using Infrared Thermography. ROCK MECHANICS AND ROCK ENGINEERING, 56(9), 6337-6355 [10.1007/s00603-023-03389-x].

Quantitative Evaluation of the Fracturing State of Crystalline Rocks Using Infrared Thermography

Franzosi, Federico
Primo
;
Casiraghi, Stefano;Colombo, Roberto;Crippa, Chiara;Agliardi, Federico
Ultimo
2023

Abstract

The fracturing state of rocks is a fundamental control on their hydro-mechanical properties. It can be quantified in the laboratory by non-destructive geophysical techniques that are hardly applicable in situ, where biased mapping and statistical sampling strategies are usually exploited. We explore the suitabilty of infrared thermography (IRT) to develop a quantitative, physics-based approach to predict rock fracturing starting from laboratory scales and conditions. To this aim, we performed an experimental study on the cooling behaviour of pre-fractured gneiss and mica schist samples, whose 3D fracture networks were reconstructed using Micro-CT and quantified by unbiased fracture abundance measures. We carried out cooling experiments in both controlled (laboratory) and natural (outdoor) environmental conditions and monitored temperature with a thermal camera. We extracted multi-temporal thermograms to reconstruct the spatial patterns and time histories of temperature during cooling. Their synthetic description show statistically significant correlations with fracture abundance measures. More intensely fractured rocks cool at faster rates and outdoor experiments show that differences in thermal response can be detected even in natural environmental conditions. 3D FEM models reproducing laboratory experiments outline the fundamental control of fracture pattern and convective boundary conditions on cooling dynamics. Based on a lumped capacitance approach, we provided a synthetic description of cooling curves in terms of a Curve Shape Parameter, independent on absolute thermal boundary conditions and lithology. This provides a starting point toward the development of a quantitative methodology for the contactless in situ assessment of rock mass fracturing.
Articolo in rivista - Articolo scientifico
Cooling experiments; Fracture density; Fracture intensity; Fractured rock; Infrared thermography; X-Ray computed tomography;
English
4-giu-2023
2023
56
9
6337
6355
open
Franzosi, F., Casiraghi, S., Colombo, R., Crippa, C., Agliardi, F. (2023). Quantitative Evaluation of the Fracturing State of Crystalline Rocks Using Infrared Thermography. ROCK MECHANICS AND ROCK ENGINEERING, 56(9), 6337-6355 [10.1007/s00603-023-03389-x].
File in questo prodotto:
File Dimensione Formato  
Franzosi-2023-Rock Mech Rock Engineer-VoR.pdf

accesso aperto

Descrizione: Original Article
Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Licenza: Creative Commons
Dimensione 7.9 MB
Formato Adobe PDF
7.9 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/419698
Citazioni
  • Scopus 2
  • ???jsp.display-item.citation.isi??? 2
Social impact