A method for evaluating the effect of crack geometry on the mechanical behavior of cracked rock masses

Discontinuities like faults and joints (called cracks) are of widespread occurrence in rock masses in situ, with very complicated geological setting. The complexity, especially in their geometry, is no doubt a major obstruction to develop a useful theory for evaluating the mechanical behavior of cracked rock masses. An index measure (called fabric tensor) which has been introduced to show crack geometry is further discussed in this paper to see if it is useful for evaluating the mechanical behavior of rock masses in situ. Based on some acceptable simplification, an overall elastic compliance for cracked materials is successfully formulated in terms of the fabric tensor. Furthermore, with the help of geometrical probability, the fabric tensor is expressed in terms of in situ measurable quantities. These results strongly suggests that the concept of fabric tensor is useful in the analysis of cracked rock masses.