Bleeding characteristics and water migration mechanism of backfill slurry
Yang Liuhua
Wang Yongbin
Fu Botao
Fu Shigen
Li Zhentao
Gong Jian
Abstract：Objectives This study aims to elucidate the correlation mechanism between the bleeding charac-teristics of backfill slurry and mesoscopic water migration,and to reveal the influence of macro-meso struc-tural evolution on the bleeding process.Methods An orthogonal experimental design was conducted to test fluidity,bleeding rate,and settling rate.Range analysis and efficacy coefficient calculations were com-bined with a Matlab-based 3D visualization multi-factor coupling model to determine the optimal mix ratio.Nuclear magnetic resonance(NMR)was used to analyze the mesoscopic water migration characteristics of the optimal slurry at standing times of 5,30,60,90,120,and 180 minutes.Results The optimal mix ra-tio was identified as a cement-tailings ratio of 1:8,a mass concentration of 74%,and a water-reducer dos-age of 1%.The significance order of factors affecting bleeding rate was:mass concentration>cement-tailings ratio>water-reducer dosage.NMR results indicated that in high-solid-concentration backfill slurry,adsorbed water was the dominant form;pore water acted as a dynamic transitional state,with fluctuating peak areas reflecting the balance between adsorbed water release and interfacial re-adsorption;and free wa-ter increased with prolonged standing time.Conclusions The bleeding process of backfill slurry can be di-vided into four distinct stages:induction period,acceleration period,constant period,and stabilization pe-riod.Water migration follows the pathway of adsorbed water→pore water→free water.The migration rate is slowest during the induction period,peaks in the acceleration period as adsorbed water rapidly converts to free water,remains rapid in the constant period,and becomes restrained in the stabilization period,result-ing in a steady bleeding state.This study provides insight into the mechanism linking bleeding characteris-tics to mesoscopic water migration and provides a theoretical basis for optimizing backfill parameters in deep mining.
Keywords：tailings pondmulti-objective optimizationslurry bleedingwater migrationmesoscopic evolu-tion
Publication Date：2025-11-30
Online Publishing Date：2025-10-22(First online date of this platform, not the publication date of the document)
Pages：9( 55-63 )