Perpustakaan Digital ITB

Underground mining will always be faced with the problem of deformation and instability of the rock mass around the tunnel. It is very important to analyze the stability of the tunnel, especially on the stopes where sill pillar is diminishing on cut and fill method. The diminished sill pillar will have reduced strength to withstand the load so that deformation will be greater. Monitoring was conducted to determine how much deformation has occurred. This monitoring are expected to be material for analyzing the stability of stope. Analysis of stope may use the concept of the value af Factor of Safety (FoS) where the value can be used as reference for subseguent stope opening. This research utilize numerical modeling using finite element method in which the boundary conditions on the tunnel are adjusted to the result of convergentmeters monitoring. Characteristic material follow the Mohr-Coulomb collapse and calculated in elastic and plastic. FoS caleulation use the strength factor calculation and Mohr-Coulomb failure criteria. The result indicate that the material in the observation has plastic behavior and also characterized by large change of strain. The strength factor grant smallest FoS with FoS on the left walls, right walls, and roof are 1.24, 1.72, and 1.02, respectively.