Horizontal pressure on barricades for backfilled stopes. Part I: Fully drained conditions

Abstract

Stope backfilling is used in underground mines to provide a safer working space for personnel and machinery. To ensure a secure application of backfill, it is critical to accurately evaluate the pressures exerted on the walls and barricades placed near the base of the stope to retain the fill materials. In this paper, existing solutions for evaluating the stresses on barricades are reviewed. The authors then propose a new three-dimensional analytical solution that takes into account the stress transfer from the backfill to the walls in both the stope and access drift. In particular, the solution considers the influence of the barricade position within the drift on the stress state. Comparisons are made between the proposed solution, physical model test results, and numerical simulations. The good agreement between various results indicates that the proposed formulation provides a good estimate of the pressure on a barricade. The solution presented here is applicable to fully drained backfill (without water-pore pressure); the solution for saturated backfill is given in a companion paper (see Part II, this issue). Résumé :Le remblayage des chantiers est utilisé dans les mines souterraines afin de maintenir un espace de travail sécuri-taire pour le personnel et les équipements. Afin d'assurer une bonne performance du remblai, il est essentiel d'évaluer de façon représentative la pression exercée sur les murs et sur les barricades installées près de la base du chantier pour retenir les matériaux de remblayage. Dans cet article, des solutions existantes pour évaluer les pressions sur les barricades sont revues. Les auteurs proposent ensuite une nouvelle solution analytique tridimensionnelle qui prend en compte le transfert des contraintes du remblai aux parois dans le chantier remblayé et dans la galerie. Cette solution tient compte l'influence de la position des barricades sur l'ampleur des contraintes. Des comparaisons sont faites entre la solution analytique, des résultats d'essais sur un modèle physique et des simulations numériques. La bonne concordance entre ces divers résultats indique que la formulation proposée représente bien la pression exercée sur les barricades. La solution présentée ici est applicable aux remblais drainés (sans pression interstitielle); une solution pour les remblais saturés est donnée dans un article complémentaire (voir Partie II, ce numéro).

Numerical and theoretical research on stress distribution in the loosening zone of the trapdoor problem

“…Comparison results indicate that the predictions from the proposed Equation 20 match well with numerical and model test results while the predictions of Terzaghi's theory are slightly larger than the model test and numerical results. Figures 15 and 16 show the comparisons between calculation results of Equations (23) and (24) and the recorded stress distribution of the numerical trapdoor tests when δ = 0.02H (at the end of simulation). Both the theoretical and numerical results of this paper indicate that the vertical stress at the two sides of loosening zone is larger than that in the middle.…”

“…On the aspect of theoretical studies, Aubertin et al 22 and Li and Aubertin [23][24][25] proposed a series of analytical or semianalytical solutions to calculate the pressure generated by backfill in backfilled stopes. Van Eekelen 26 raised a limit-state equilibrium model with a concentric arch for the design of pile-supported embankments.…”

A numerical study into factors affecting stress and pore pressure in free draining mine stopes

“…Some of these models ignore pore pressures, despite the fact that mine backfill is deposited hydraulically in a slurry-like state [16,15]. Other models simply impose hydrostatic pore pressure conditions [17].…”

Total and Effective Stresses in Backfilled Stopes during the Fill Placement on a Pervious Base for Barricade Design

“…The construction of a confining structure, called barricade (bulkhead), in the draw-point at the base of the stope is necessary to hold the slurried backfill in place. The stability of the barricade can thus become a critical concern as the barricade failures, previously reported in the literature, have mostly resulted in serious consequences, such as damage of equipment, personal injury, and even loss of lives [21][22][23][24][25][26][27][28][29][30].…”