A special three-dimensional boundary element method has been developed for the simulation of the development of fracture zone in rock mass. This approach comprises a boundary element method and a three-dimensional tessellation mesh generator. By using the tessellation generator, a set of pre-defined potential fractures is defined, and the fractures activate when the failure criterion is exceeded. This approach is justified by the reproduction of features observed in laboratory simulations of fracturing in blocks of rock subjected to compression. An attempt is then made to explain some of the attributes of fracture zone surrounding underground openings.

Eine spezielle drei-Dimesionen Grenze Element Methode ist entwickelt zu simulieren die Entwicklung der Fraktur Zone in der Steinmasse. Diese Untersuchung benutzt eine Grenze Element Methode und ein drei-Dimensionen tessellation Masche Generator. Durch das Benutzen des Tessellation Generator, ein Satz der vor-bestimmt potentielle Fraktur ist festgelegt. Die Fraktur wird betaetigen, wenn das gescheiterte Kriterium ist uebersteigt und sind in dem Verscheiben- Abbrechen Element eingeschlossen. Diese Untersuchung ist von der Reproduktion der Fraktur justiert, die ins Labor beobachtet wird, um die Fraktur in der von der Kompression unterworfenen Steine zu simulieren. Ein Versuch ist gemacht, um einige Eigenschaften der Fraktur Zone um die untertageoeffnung zu erklaeren.

Une methode tridimensionelle speciale de element frontière a ete developee pour la simulation du development d'une zone fracturee dans la massive roche. Cette approche comprend une methode de element frontière et un generateur de maillage de la mosaïque tridimensionelle. En utilisant le generateur de mosaïque, une serie des fractures potentielles predefinies est definie avec d'une procedure de la triangulation de Delaunay. Les fractures activent lorsque le critère de rupture est depasse et sont inclues dans les elements du deplacement discontinuite. Cette approche est justifiee par la reproduction des caracteristiques observees dans le laboratoire, les simulations des blocs de roche fracture et sujetes en compression. La tentative est alors fait pour expliquer quelques arttributs d'une zone fracturee alentours les ouvrages sousterrains.


As only the boundary of domain requires discretization, the boundary element method is very efficient and suitable for the semi-infinite or infinite rock engineering problems. The material domain of a rock engineering problem generally is inhomogeneous and discontinuous, however, most of the numerical models assume the domain to be homogeneous, isotropic, and linearly elastic.

The constitutive properties of rock discontinuities has been an important subject under development for the last two decades1,2. The linear constitutive models which defines constant stiffness relating the rate of change of stress with respect to displacement have the advantage of simplicity and are widely used for analyzing engineering problems3. Such models, however, cannot accurately simulate the behaviour of the rock discontinuities. In order to more properly simulate the behaviour of the rock discontinuities, it is essential to apply more precise constitutive models.

The displacement discontinuity element, boundary element with displacement discontinuities (fictitious crack) over the element, is particularly suitable to model rock discontinuities. The two-dimensional boundary element methods using displacement discontinuity elements were applied to simulate underground excavation with non-linear discontinuities4,5.

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