Etude comparative des contraintes triaxiales dans le remblai en pate selon la portee des chantiers.

摘要

Stresses induced in a stope during the placement of pastefill, especially on a barricade at the base of the stope, are an important consideration for a mining operation. Little data is available regarding the magnitude of these stresses. In order to better understand the loading phenomenon of pastefill on fences, and to ensure an adequate safety factor, two stopes of different spans were instrumented at the Doyon Mine (Cambior Inc.) The results of this instrumentation programme indicate that, for the same height of pastefill, there exists a direct link between the width or span of a stope and the magnitude of the induced stresses This relationship is due to a phenomenon known as the arch effect, and can be explained by the interactions that develop between the rock mass and the backfill, and which result in a load transfer along the walls of the stope. The results of this investigation show that the magnitude of the stresses depends on the distance between the walls of the stope.;Pastefill is also characterised by changes to its physical-chemical properties as it cures. Current instrumentation does not permit testing of freshly poured backfill in open stopes, at least in an industrial setting. As a result, analytical solutions have been proposed, and validated with experimental data from the Doyon Mine. These solutions make it possible to estimate the cohesion and friction angle of a material as a function of its uniaxial compressive strength, binder content, and curing time.