Study on Fluidity Behaviour of Cemented Foamed Backfill Slurry Based on Water Film Thickness Theory

Abstract

This paper is aimed at investigating the evolution of fluidity and rheological properties of fresh CFB with different foaming agent dosage and particle size distributions (PSD) of filling aggregate, and revealing the mechanism of fluidity evolution based on water film thickness (WFT) theory. The results show that the flowability (spread diameter) of fresh CFB increases with increasing particle size of filling aggregate (D(4, 3)∈[192 μm, 398 μm]) and decreases with increasing foaming agent dosage. The former is related to the particle gap and specific surface area, while the latter to the number and distribution of bubbles in the slurry. PFC3D was used to simulate the accumulation model of bubbles and solid particles. At the calibrated simulation error coefficient of 1.1, the relationship between water film thickness of fresh CFB and spread diameter of slurry was analysed. The bubbles in slurry change the water film thickness by changing the overall packing compactness and specific surface area of fresh CFB, and then affect its fluidity.

Keywords

• foamed backfill
• fluidity
• foaming agent dosage
• particle size of filling aggregate
• water film thickness