M. Mauldon, KEYBLOCK PROBABILITIES AND SIZE DISTRIBUTIONS - A FIRST MODEL FOR IMPERSISTENT 2-D FRACTURES, International journal of rock mechanics and mining sciences & geomechanics abstracts, 32(6), 1995, pp. 575-583
Citations number
22
Categorie Soggetti
Geosciences, Interdisciplinary","Mining & Mineral Processing
Keyblock size distributions are of fundamental importance in many bran
ches of applied rock mechanics, including tunnelling, mining and rock
slope engineering. While strongly dependent on discontinuity parameter
s such as spacing, persistence (or size) and orientation, keyblock siz
e distributions and occurrence probabilities depend additionally on th
e size, shape and orientation of the free surface. Previous analytical
models for keyblock size have been based on the assumption of infinit
e (persistent) discontinuities. In this paper a general model for the
size distribution and probability of occurrence of simple 2-D keyblock
s for arbitrary distributions of discontinuity size is developed. The
method is appropriate for blocks formed by sparse fractures in tunnels
or slopes. Closed form solutions are obtained for discontinuities of
constant size. Application to the 3-D case is discussed and extension
of the method to 3-D outlined. The results, which may depart significa
ntly from predictions based on the assumptions of infinite fractures,
ave directly applicable to rock support and excavation design.