Discrimination of damage and fracture information in rock and soil based on image measurement

Based on CT images and utilizing analysis of physical characteristic value and naked eye observational estimate respectively, the time of damage appeared in the rock or soil is estimated so as to prove the limits of simple observation by eye. Then, using contour method determines the location of damage and judges its extending direction. Through analyzing curve of maximum and minimum of CT number and loading within specimen, the subarea thresholds of non-damage part, damage part and fracture part are determined. Moreover, binary images of each part are obtained under these thresholds. Finally, shape, geometry and physical characteristic value of these binary images are measured quantitatively.