Numerical analysis of the failure mechanisms of sill mats made of cemented backfill
Alpha Mamoudou Talibe Keita, Abtin Jahanbakhshzadeh, Li Li
Abstract
Sill mat (SM) made with cemented backfill is an important structure in underground mining with backfill. Determining its minimum required strength is key to ensure economic and safe design . In 1991, Mitchell proposed a model with immobile walls. Four failure modes were possible. Recently, Pagé and co-workers showed that the failure mode of SM in a narrow stope is crushing when the entire underlying excavation is realized in one step . In this paper, the influences of stope width and sequence of underling excavation on the failure modes of SM are numerically analyzed. The results show that crushing remains the main failure mode for narrow stopes. Failure by flexure becomes possible when SM is wide enough with underlying excavation in several thin layers. Failures by rotation and caving are also possible, depending on the wall inclination and SM span Stronger SM is necessary when mine depth and, SM thickness, and stiffness increase.