Stability Analyses of Waste Rock Barricades Designed to Retain Paste Backfill

Abstract

Cemented paste backfill (CPB) is widely applied in underground mines around the world. Prior to stope backfilling, barricades need to be built in drifts near drawpoints to retain the flowable fill. A number of reported barricade failures have shown that barricade stability is critical for ensuring successful and safe application of backfill. The barricades are usually made of high-strength materials such as bricks, concrete blocks, or reinforced shotcrete. Alternatively, barricades made of waste rocks are becoming popular because of their simple and low-cost construction. A simple solution was proposed for sizing waste rock barricades (WRBs) by considering the limit equilibrium of a three-dimensional (3D)-rectangular block. More recently, the authors modified this solution by considering the global stability of trapezoidal barricades, but the local stability was not taken into account. Consequently, the size of the crest can be underestimated, leading to a nonconservative design. In this paper, a more complete solution is proposed, considering both the global and local stabilities of trapezoidal WRBs. The analytical solution was calibrated and validated using numerical modeling. The flexibility and validity of the proposed solution were further tested with complementary simulations. Sample calculations are also performed here to show the application of this solution and to illustrate the effect of key influencing factors on barricade design.