基于水膜厚度理论的发泡充填料浆流动性能试验研究

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

研究了发泡充填料浆流动性和流变性能随发泡剂量和充填骨料粒径变化的演变规律,并基于水膜厚度理论揭示流动性的影响机制。结果表明,发泡充填料浆的流动性能(扩展度)随着充填骨料粒径(D(4,3)∈[192μm,398μm])的增加而增大,随着发泡剂量的增加而减小,前者与颗粒间隙及比表面积有关,而后者则与浆体中气泡的数量和分布形态有关。利用PFC^(3D)建立了气泡与固体颗粒的堆积模型,在标定模拟误差系数为1.1的基础上,研究了发泡充填料浆的水膜厚度随料浆扩展度的演变规律。由此可知,浆体中的气泡通过改变发泡料浆整体堆积密实度和比表面积进而改变水膜厚度,影响料浆流动性。

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)∈[192μm,398μm])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.PFC^(3D) 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.