YANG L H, WANG Y B, FU B T，et al．Study on bleeding characteristics and water transport mechanisms in backfill slurry［J］.Journal of Henan Polytechnic University( Natural Science) ，doi:10.16186/j.cnki.1673-9787. 2024030076

doi: doi:10.16186/j.cnki.1673-9787.2023050076

Received：2025-03-31

Revised：2025-05-19

Online：2025-06-05

Study on bleeding characteristics and water transport mechanisms in backfill slurry

Yang Linghua^1,2, Wang Yongbin¹, Fu Botao², Fu Shigen², Li Zhentao², Gong Jian³

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

Abstract: Filling mining technology eliminates environmental and safety threats from tailings pond by converting industrial waste materials such as tailings and fly ash into backfill materials through solid waste recycling. The bleeding phenomenon in backfill slurries significantly affects the filling roof contact rate and the strength of the consolidated backfill, which directly impacts the overall stability of tailings reservoirs and the effectiveness of backfilling. [Objective] This study aims to elucidate the correlation mechanism between the bleeding characteristics of backfill slurries and mesoscale water migration, as well as to uncover the influence of macro-mesostructural evolution on the bleeding process. [Methods] An orthogonal experimental design was conducted to test fluidity, bleeding rate, and sedimentation rate. Range analysis and efficacy coefficient calculations were combined with a Matlab 3D visualization model for multi-factor coupling effects to determine the optimal mix ratio. Nuclear magnetic resonance (NMR) technology was used to analyze the mesoscale water migration characteristics of the optimal slurry under standing times of 5, 30, 60, 90, 120, and 180 min. [Results] The optimal mix ratio was identified as cement-tailing ratio 1:8, mass concentration 74%, and water-reducer dosage 1%, with the significance order of factors affecting bleeding rate being mass concentration > cement-tailing ratio > water-reducer dosage. NMR results showed that adsorbed water was the dominant form in the high solid-concentration backfill slurry, pore water acted as a dynamic transitional state with fluctuating peak areas indicating its participation in the balance between adsorbed water release and interfacial re-adsorption, and free water increased with standing time. [Conclusion] The bleeding process of backfill slurries can be categorized into four distinct: induction period, acceleration period, stabilization period, and steady state. Water migration follows the transformation pathway of "adsorbed water → pore water → free water," with the slowest rate in the induction period, the fastest rate of adsorbed water conversion and bleeding in the acceleration period, and stabilized bleeding in the steady state. This study reveals the mechanism linking bleeding characteristics to mesoscale water migration, providing a theoretical basis for optimizing parameters in deep mining backfill engineering.

Key words: tailings pond; multi-objective optimization; slurry bleeding; water transport; mesostructured evolution

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