The MIT geologic stochastic fracture model, which comprises four stochastic processes imitating the real geological fracturing processes, produces 3D fracture networks in rock. In this paper, the additional development of the third stochastic process to consider crustal faults is briefly described. The model is then used in two case studies of fracture patterns related to crustal faults. First, the fracture networks occurring during various stages of the faulting process in the granitic rock of the Mount Abbot quadrangle are qualitatively reproduced. Then, the major fracture networks in the Boston Basin are simulated; in this case, the parameters "fracture intensity, fracture size, fracture spacings along boreholes and trace lengths on outcrops" of the simulated pattern are quantitatively compared to reality.
Le modèle geologique stochastique de fractures developpe au MIT, qui comprend quatre processus stochastiques imitant les processus geologiques reels de fracturation, permet de produire des reseaux tridimensionnels de fractures en rocher. Cet article presente brievement Ie developpement du troisieme processus stochastique pour prendre en compte l'influence des failles. Tout d'abord, les reseaux de fractures generes lors de differentes etapes de creation de failles au sein des granites de la region du Mont Abbot sont reproduits qualitativement. Ensuite, les principaux systemes de fractures dans la region du Bassin Sedimentaire de Boston sont simules; dans ce cas, les parametres des reseaux simules tels que "intensite de fracturation, taille de fracture, espacement de fractures le long de forages et longueur des traces sur des affleurements" sont compares quantitativement à la realite.
Das am MIT entwickelte geologisch-stochastische Kluftmodell, welches aus vier Prozessen besteht, mit denen die natuerlichen Klueftungsvorgange nachgebildet werden, produziert dreidimensionale Kluftsysteme. In diesem Artikel wird zuerst die zusatzliche Entwicklung im dritten Prozess zur Nachahmung von verwerfungsbezogenen Klueftungsprozessen beschrieben. Dem wird die Anwendung in zwei Fallen beschrieben. Zuerst werden die Kluftsysteme, welche in verschiedenen Phasen des Verwerfungsprozesses in der Mt.Abbot-Gegend auftreten, qualitativ nachgebildet. Dem folgt die Simulation der wichtigsten Kluftssysteme im Bostoner Becken; in diesem Fall könnnen die Kluftparameter "Intensitat, Grösse, Abstand entlang Bohrlochern, und Kluftspurlangen in Aufschluessen" quantitaitiv mit den Beobachtungen in der Natur verglichen werden.
Modeling of fracture patterns and, particularly, stochastic modeling of fracture patterns forms the basis for numerous rock mechanics and rock engineering analyses used to solve flow-, slope stability- and tunnel stability problems. The model described here represents a further development of earlier models created at MIT (Veneziano, 1978; Dershowitz, 1986; Lee et al. 1990), which were similar to models developed elsewhere (e.g, Martel et al., 1991). What is described here is the latest step in the work on geometric-mechanical modeling started by Ivanova (Ivanova et al., 1995; Ivanova, 1998).
The geometric-mechanical model produces complex fracture systems in three-dimensional space, as the geometric models do. In contrast to the purely geometric models, it geometrically imitates the mechanical processes underlying geologic genesis of fractures. The new model is hierarchical since the produced fractures are grouped into hierarchically related fracture sets. Finally, the model is stochastic because the main processes generate the geometrical features according to statistical distributions. The required inputs for the model are: the modeling volume(s), the fracture intensity as expressed by P32, i.e. total fracture area per volume (see Dershowitz 1986), the expected area E[A] (or equivalent radius E[Re])