YANG L H, WANG Y B, FU B T,et al.Bleeding characteristics and water migration mechanism of backfill slurry[J].Journal of Henan Polytechnic University(Natural Science) ,2025,44(6):55-63.

doi:10.16186/j.cnki.1673-9787.2025030076

Received: 2025/03/31

Revised: 2025/05/31

Published: 2025/10/14

Bleeding characteristics and water migration mechanism of backfill slurry

Yang Liuhua1,2, Wang Yongbin1, Fu Botao2, Fu Shigen2, Li Zhentao2, Gong Jian3

1.School of Civil Engineering， Henan Polytechnic University， Jiaozuo  454000， Henan， China；2.China Academy of Safety Science and Technology， Beijing  100083， China；3.School of Civil Engineering， Zhengzhou University of Technology， Zhengzhou  450044， Henan， China

Abstract: Objectives This study aims to elucidate the correlation mechanism between the bleeding characteristics of backfill slurry and mesoscopic water migration， and to reveal the influence of macro-meso structural 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 combined 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 ratio was identified as a cement-tailings ratio of 1：8， a mass concentration of 74%， and a water-reducer dosage 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 water increased with prolonged standing time. Conclusions The bleeding process of backfill slurry can be divided into four distinct stages： induction period， acceleration period， constant period， and stabilization period. 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， resulting in a steady bleeding state. This study provides insight into the mechanism linking bleeding characteristics to mesoscopic water migration and provides a theoretical basis for optimizing backfill parameters in deep mining.

Key words: tailings pond; multi-objective optimization; slurry bleeding; water migration; mesoscopic evolution