A solution to estimate the total and effective stresses in backfilled stopes with an impervious base during the filling operation of cohesionless backfill

Abstract

SummaryMining backfill is commonly used in underground mines. A critical concern of this practice is to evaluate the pressures and total stresses in backfilled stopes to ensure a safe and economic design of barricades, constructed to retain the backfill. When a slurried backfill is placed in a mine stope, excess pore water pressure (PWP) can instantaneously generate and progressively dissipate. The dissipation of the excess PWP and consolidation lead to the development of effective stresses, which in turn lead to an arching effect in the backfilled stope. Until now, arching effect has been largely considered for stress estimation in dry or submerged backfill. The former corresponds to the final state at the end process of the drainage and consolidation of the backfill with a pervious while the latter with an impervious barricade. However, previous studies have shown that the most critical moment for the stability of barricades is during the stope filling. Therefore, the design of barricades requires a proper estimation of the pressure and total stresses during the filling operation. This in turn needs joint consideration of the arching effect and consolidation of the backfill. In this paper, a new solution is developed to evaluate the pressures and stresses in backfilled stopes during the filling operation of cohesionless backfill by considering the self‐weight consolidation and arching effect. The proposed solution is validated by numerical modeling with Plaxis2D. It can thus be used to evaluate the pressures and stresses in backfilled stopes during the stope filling with an impervious barricade.

Natural mixing behaviour of waste rocks poured in a paste backfill

“…However, almost all publications on mining backfill have focused on the behaviour of a single type of backfill, including the extensive works conducted by Li and co-workers over the past two decades (Aubertin et al 2003;Béket Dalcé et al 2019;El Mkadmi et al 2014;Jaouhar et al 2018;Jaouhar & Li 2019;Keita et al 2021aKeita et al , 2021bLi et al 2003;Li et al 2005;Li & Aubertin 2012;Li 2014aLi , 2014bLiu et al 2017aLiu et al , 2017bLiu et al , 2018Pagé et al 2019;Qin et al 2021aQin et al , 2021bWang et al 2021aWang et al , 2021bWang & Li 2022;Yang et al 2017Yang et al , 2018Zhai et al 2021;Zheng et al 2019Zheng et al , 2020aZheng et al , 2020bZheng et al , 2020c. Research on the natural mixing behaviour between the waste rocks and paste backfill is absent in the literature.…”