Investigating Cooling Rate Indices: An InfraRed Thermography Study at the Požáry Field Laboratory, Czech Republic

Understanding thermal variation in rock masses is fundamental in determining rock deformation, which can lead to more significant movements such as rockfalls. Directly acquiring this information in the field is still complex and problematic, particularly in inaccessible areas. Therefore, correlations are still an effective tool to compensate for this limitation. Furthermore, recently, InfraRed Thermography (IRT) has proved capable of capturing the intrinsic properties of rocks.

Consequently, we implement a method to evaluate the porosity and the elastic moduli using relatively simple thermal data acquisition, capitalising on the different thermal cooling behaviour of different rock slope sectors. Thermograms were acquired at 10-minute intervals in laboratory and field settings, with correlations evaluated using a Cooling Rate Index (CRI). Concurrently, geotechnical parameters of core samples from these sectors were analysed to explore their mechanical differences. In these zones, in which mechanical behaviours are quite distinct, the experiments carried out in the TIR band have highlighted many discrepancies.

In this test case, the thermal time-lapse analysis revealed a correlation between physical properties and cooling rates in the Požáry field laboratory, reinforcing previous findings that cooling rates can distinguish between different rock textures. However, further validation is needed in various materials to generalise the based thermal parameter characterisation. By elucidating the temperature distribution and dynamics within the rock slope, this study may contribute to understanding rockfall dynamics in temperate climates, facilitating the development of effective rock mass characterisation strategies.