Analytical solution for stress distribution in cementitious backfills considering stope inclinations

Creative Commons License

Yan B., Yılmaz E.

Recep Tayyip Erdogan University Journal of Science and Engineering, vol.1, no.2, pp.26-33, 2020 (Peer-Reviewed Journal)


To enhance stope stability and decrease surface waste disposal, fill is used in underground mines. Moreover, cementitious fill is used as structural support element for maximizing the extraction ratio of run-of-mine ore in unevenly dipping ore deposits. Assessing the stress distribution in the backfill and neighboring rock mass is of great importance to the design of backfilled stopes. Inappropriate design of these stopes can cause the backfill failures, thus resulting in devastation of stope walls, production delays and even losses in ore dilution form, and security matters. Until now, analytical solutions have been developed for obtaining the stresses in vertical openings and there is a clear need for works which deal the stresses developed in inclined backfilled stopes. In this study, an improved analytical model is presented to solve the non-uniform distribution of stress in backfill on stope cross-section when the friction force between the footwall and hanging wall are not equal. Considering the force balance of the arc differential element, the stress distribution in the backfill is derived. The improved model was compared with the existing model. It has been demonstrated analytically that the existing model underestimates the fill stress when the stope inclination becomes larger. Besides, when the surrounding mass produces a large deformation and squeezes backfill, the major principle stress arch happens. As a result, the findings of this study will offer the technical knowledge needed to develop a cost-effective backfill structure in underground mines that are environmentally friendly, safe and durable.