The impact of ultrasonic waves on physical properties of rocks
The ever-decreasing sources of fossil fuels such as coal, oil and gas have imposed new needs for using more sustainable forms of energy. Alternatively, employing nuclear power for electricity production may also result in significant reductions of carbon dioxide emissions coming from the combustion of fossil fuels. This greenhouse gas has been considered as one of the key contributors to climate change and global warming. Despite that nuclear waste may have been safely managed for years, research in this area is continuous especially for resolving this problem in the most practical and realistic way. Within this context, this project focused on studying the structural condition of the rock barrier around deep underground laboratories. For this purpose, specialised tools and interpretation techniques have been developed for ultrasonic surveys in order to assess the feasibility of this nuclear waste storage. Apart from the tools and techniques, a set of useful results was also gathered from extensive numerical modelling studies employing a dynamic wave propagation code. This data set may substantially facilitate the investigation of the effect rock-mass characteristics including crack density, size and orientation as well as fluid content have on ultrasonic transmission properties. After running 667 models, detailed information is being provided on the variations in the phase and amplitude spectra in comparison to those incurred by wave passage through a perfectly elastic body. This data may be correlated with other data coming from both the in situ and laboratory tests in order to provide effective means of more reliable interpretation as far as the physical properties and behaviour of the rock are concerned. Except for the radioactive waste management, this result may also find significant applications in areas where continuous and non-destructive testing of brittle materials such as concrete and metals is undertaken. For instance, in mining and in petroleum sectors as well as in seismological studies and civil engineering for structures including dams, tunnels and bridges.
