An Analytical Solution of Gibson's Model for Estimating the Pore Water Pressures in Accreting Deposition of Slurried Material Under One-Dimensional Self-Weight Consolidation. Part I: Pervious Base

Every year, mines produce a large amount of tailings that must properly be managed. For most cases, the tailings are sent by pipes and disposed of in tailings dams. Another more and more common practice is to send a part of the tailings with or without cement binder to underground to fill mine voids (stopes). In civil engineering, a similar practice is the deposition of dredged sludge pumped and confined in a containment structure (dam for most cases). In these cases, an important challenge is to determine the pore water pressure (PWP) associated with the self-weight consolidation of the slurried backfill disposed layer by layer. A solution to the self-weight consolidation of accreting (increase in thickness) deposition of slurried material was first proposed by Gibson in late 1950s. Recently, it has been revisited and applied to mine stopes backfilled with slurried materials. The solution can only be evaluated numerically. In this paper, a truly analytical solution is proposed that is based on the Gibson approach and can be readily used to manually calculate the variation and evolution of the PWP within accreting deposition. The effect of the filling rate, fill height and backfill properties on the variation and evolution of the PWP is analyzed. The solution is proposed for accreting deposition of slurried backfill placed on pervious base. An analytical solution for estimating the PWP within slurried backfill disposed on impervious base is presented in a companion paper.