Failure mechanisms of high rock slopes in hard rock were studied by means of numerical modeling. The conditions for the occurrence of different failure mechanisms, such as circular shear and large scale toppling failure were quantified. Furthermore, the different phases in the failure process (initiation and propagation) were described in detail. The deformability of the rock mass proved to be an' important parameter: governing slope behavior. Hence, numerical models are preferred over e.g, limit equilibrium methods in which rigid body movements are assumed. Finally, guidelines for how to analyze slopes in certain geomechanical environments were formulated.
Les mecanismes de rupture de grands pans de rocher ont ete etudies au moyen des model numeriques. Les conditions d'apparition de differents mecanismes de ruptures comme par exemple le cisaillement circulaire ou la rupture, en basculement à grande echelle, ont ete quantifies. De plus, les differentes phases du processus de rupture (initiation et propagation) ont pu être decrites en details. La deformabilite de la masse rocheuse s'est revelee être un parametre important gouvernant Ie comportement du pan de rocher. C' est pourquoi, les modeles numeriques ont ete preferes à par exemple la methode de l' equilibre limite qui suppose le mouvement rigides des corps. Pour finir, des recommandations sont formulees pour l' analyse de pentes dans differentes conditions geomecaniques.
: Die Bruchrilechanismen von hohen Böschungen wurden mit Hilfe von numerischen Modellen untersucht, Die Bedingungen fuer das Auftreten der verschiedenen Bruchmechanismen wie zirkelförmiger Schubbruch und großmaßstablichen Kippungen wurden festgelegt. Weiterhin konnten die verschiedenen Phasen der Bruchentwicklung im einzelnen beschrieben werden. Die Verformungseigenschaften des Gebirges erwiesen sich als ein wichtiger Parameter der das Verhalten der Böschung steuert. Folglich werden numerische Modelle den GrenzgIeichgewichtsmethoden vorgezogen, in denen Starrkörperverhalten vorausgesetzt wird. Schließlich werden Richtlinien fuer die Analyse von Böschungen unter verschiedenen geomechanischen Voraussetzungen vorgeschlagen.
Increasing mining depths in open pit mining results in an increased risk of large-scale stability problems: Unfortunately, failure mechanisms in high slopes are, in general, poorly understood. This is particularly true for hard rock slopes, since there are few cases of large-scale slope failures in high (300–500 meter) hard rock slopes. Even for slopes in weaker rocks - which have experienced large scale failure - several fundamental issues are still largely unresolved. These include:
the conditions for the occurrence of different failure mechanisms,
the conditions for failure initiation,
the shape and location of the failure surface, and
the development and propagation of a large scale failure.
Consequently, there is a need to study these aspects, for commonly 1 observed and assumed failure mechanisms. This was, the objective of the. study presented in this paper.
Numerical modeling was used to, investigate failure mechanisms. Models. were used as a "laboratory", in, which extensive parameter studies were conducted to identify factors governing various failure mechanisms. These parameter studies can by far exceed the number of laboratory experiments (or field tests) normally afforded, and in much shorter time. Modeling was not intended to simulate a particular case in detail
