A Review on Evaluation of Microstructural Parameters to Estimate the Strength of Virtually Isotropic Rock Materials

The quantification microstructural parameters has gained significant attention to estimate the strength of rock materials. Some researchers have qualitatively explained the influence of microstructural parameters on rock mechanical properties and many developed empirical relations between various microstructural indices and engineering properties of different rock types. A comprehensive review on the relation between microstructure and strength of rock materials has been carried out in this study based on the available literature and the tests performed on granite and sandstone from Malanjkhand and Kothagudem respectively. It has been observed that the correlation of rock strength with mineral content, textural parameters and micro-crack patterns does not signifies any perceptible correlation or any definite trend. This is attributed to the fact that rock strength is a manifestation of cumulative responses of a number of microstructural parameters and thus, correlating rock strength with any single parameter would overlook the impact of others. The study also discusses the challenges and potential benefits of both quantitative and qualitative analysis of microstructure in rock mechanics, providing a way forward for future research in the field. It is ascertained that microstructural studies are time consuming approach and involve significant limitations when quantifying the parameters from the microscopical images and relating them individually with strength of the rocks. However, they might be an important aspect in comprehending the variation in strength and deformation of rock materials and in this respect the implication of modern technological setups would be efficient over the conventional methods.