Modelling of progressive block-flexural toppling failure using numerical distinct element method (Case study: South Pars special zone)

The block-flexural toppling due to the involving the multiple failures mechanisms (e.g. slip-rotation-bending and shear) has always been considered and analysed only in the form of kinematic approaches and its instabilised mechanism has been much underestimated. In this paper, we have tried to evaluate the block-flexural toppling failure mechanism by application of distinct element method (DEM) by UDEC software which is considered as the most complex instability type in the discontinuous rock slopes assessment. For this purpose, a discontinuous rock slope which is located in Assalouyeh - Kangan (in South Pars Special Zone) freeway side is considered as a case study. This discontinuous marly limestone slope which is belonged to Aghajari formation is the main cause of instability and slip in freeway. According to the modelling results, the numerical methods capable to successfully simulated of progressive slip scenario the final critical sliding surface is estimated for slope under the block-flexural toppling mechanism. Also, the multiple failures mechanisms are been intuitively recognized and fully identified