Assessment of different methods for characterization of microcracks in rock samples

Cracks are one of the common features of crystalized rocks which their significant role in controlling the physical and mechanical characteristics of rocks is widely accepted. Accordingly, obtaining a true understanding and quantification of microcrack content of rocks is a valuable asset in many applications including stability of rock structures, detecting blast or quake induced damages, prospecting water or oil reserves, etc. this paper intends to introduce and analyze different methods for detection and quantification of microcracks content of rocks. For this purpose, all of these methods have been classified in two categories of direct and indirect methods. In the direct category, the computer tomography, fluorescent studies, confocal laser photography, scanning electron microscope (SEM) and polarized microscopy methods have been discussed. In the indirect category, the P-wave velocity, point load index and the BET methods have been evaluated. It can be concluded that direct methods commonly are more precise but they demand more extensive studies, while indirect methods offer some quick but less accurate results. Therefore, each person should choose one of these approaches or combination of the two based on his desired precision and the required extent of the study.

Keywords:

Microcrack , Microscopic studies , Quantification , Fluorescent , CT-scan