Analytical Solution for Stress Distribution in Cementitious Backfills Considering Stope Inclinations

Year 2020, Volume: 1 Issue: 2, 26 - 33, 30.12.2020

Baoxu Yan , Erol Yılmaz

Abstract

To enhance stope stability and decrease surface waste disposal, fill is used in underground mines. Moreover, the cementitious fill is used as a structural support element for maximizing the extraction ratio of run-of-mine ore in irregularly shaped orebodies. Assessing the stress distribution within the fill 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 the devastation of stope walls, production delays and even losses in ore dilution form, and security matters. Great effort has been made to acquire the stresses within vertical voids analytically, and there is a clear need for works which states the stress developed in inclined backfilled stopes. In this study, an analytical model is presented to explain 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 within mine fill is obtained. This 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 primary principle stress arch happens. Consequently, the outcomes of the present study will offer the knowledge needed to develop a cost-effective backfill structure in underground mines that are environmentally friendly, safe and durable.

Keywords

Cementitious Backfill, Arching, Minor and Major Principal Stress Arch, Analytical Model

Stope Eğimlerini Dikkate Alan Çimentolu Dolgularda Gerilme Dağılımı İçin Analitik Çözüm

Abstract

To enhance stope stability and decrease surface waste disposal, fill is used in underground mines. Moreover, the cementitious fill is used as a structural support element for maximizing the extraction ratio of run-of-mine ore in irregularly shaped orebodies. Assessing the stress distribution within the fill 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 the devastation of stope walls, production delays and even losses in ore dilution form, and security matters. Great effort has been made to acquire the stresses within vertical voids analytically, and there is a clear need for works which states the stress developed in inclined backfilled stopes. In this study, an analytical model is presented to explain 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 within mine fill is obtained. This 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 primary principle stress arch happens. Consequently, the outcomes of the present study will offer the knowledge needed to develop a cost-effective backfill structure in underground mines that are environmentally friendly, safe and durable.

Keywords

Çimentolu Dolgu, Kemerlenme, Küçük ve Büyük Ana Stres Arkı, Analitik Model

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