THE USE OF MODAL ANALYSIS IN THE MECHANICAL CHARACTERIZATION OF ROCK MASSES

QUANTITATIVE METHODS ARE DEVELOPED FOR DERIVING FROM MICROPETROGRAPHIC OBSERVATIONS QUALITY INDICES WHICH MAY CHARACTERIZE ROCK MASSES AT EACH POINT. THE PROCEDURES USED, THE PROCESSING OF THE RESULTS AND THE CONCLUSIONS DRAWN ARE DESCRIBED. IT IS SHOWN BY MEANS OF MICROPETROGRAPHIC MODAL ANALYSIS HOW ROCK MASSES CAN BE CHARACTERIZED AT EACH POINT BY INDICES WHICH TAKE INTO ACCOUNT THE MECHANICALLY FAVORABLE AND UNFAVORABLE INFLUENCES OF THE DIFFERENT MINERAL COMPONENTS AND THE MICROFRACTURES PRESENT IN THE ROCKS. EXAMPLES OF APPLICATION PROVING THAT SUCH INDICES CAN BE CORRELATED WITH THE DEFORMABILITY OF THE ROCKS ARE PRESENT. THE STATISTICAL METHODS USED FOR OBTAINING THESE CORRELATIONS ARE ALSO DESCRIBED. /RRL(A)/