Analysing Localisation Behaviour of Rocks using Digital Image Correlation Technique

摘要

With the advent of advanced computing technologies, applications of numerical modelling techniques have become popular among the research community. It resulted in the development of numerous constitutive models, the majorities of which are based on the macroscopic material responses simply because of the unavailability of reliable experimental data set which could not only reveal the material behaviour at a global scale but also provide the insight at local scale. Even the use of advanced experimental techniques, despite being efficient, has not furnished well in the direction of revealing localised material behaviour and limited to adding more visual effects. It highlights the importance of comprehensive results interpretation while using advanced experimental techniques. In this direction, this paper presents a new approach to analysing localisation behaviour of rocks using Digital Image Correlation (DIC) technique. For this purpose, lateral strain controlled uniaxial compression tests have been conducted on cylindrical samples of Hawkesbury sandstone. Full field strain data set obtained from DIC have been used to evaluate the localised strain evolution across and around the shear band. It further has been synchronised with macroscopic material response to provide insight into the strain localisation mechanism with reference to the overall sample response. Additionally, strain rate evaluation across the shear band has also been done. These results have been further used to evaluate the thickness of the localisation zone which itself is a much-needed micro-scale parameter for the development of any reliable constitutive model.