寇云鹏, 郭沫川, 谭玉叶, 齐兆军, 宋泽普, 宋卫东. 分级细尾砂胶结充填体早期水化放热及强度演化特性[J]. 工程科学学报, 2023, 45(8): 1293-1303. DOI: 10.13374/j.issn2095-9389.2022.07.24.002
引用本文: 寇云鹏, 郭沫川, 谭玉叶, 齐兆军, 宋泽普, 宋卫东. 分级细尾砂胶结充填体早期水化放热及强度演化特性[J]. 工程科学学报, 2023, 45(8): 1293-1303. DOI: 10.13374/j.issn2095-9389.2022.07.24.002
KOU Yun-peng, GUO Mo-chuan, TAN Yu-ye, QI Zhao-jun, SONG Ze-pu, SONG Wei-dong. Early hydration heat release and strength evolution of cemented backfill with graded fine tailings[J]. Chinese Journal of Engineering, 2023, 45(8): 1293-1303. DOI: 10.13374/j.issn2095-9389.2022.07.24.002
Citation: KOU Yun-peng, GUO Mo-chuan, TAN Yu-ye, QI Zhao-jun, SONG Ze-pu, SONG Wei-dong. Early hydration heat release and strength evolution of cemented backfill with graded fine tailings[J]. Chinese Journal of Engineering, 2023, 45(8): 1293-1303. DOI: 10.13374/j.issn2095-9389.2022.07.24.002

分级细尾砂胶结充填体早期水化放热及强度演化特性

Early hydration heat release and strength evolution of cemented backfill with graded fine tailings

  • 摘要: 对分级细尾砂胶结充填体的早期水化反应及力学演化特性进行研究,对不同灰砂比充填体料浆进行水化放热及电阻特性测试,并根据扫描电子显微镜对早期水化产物进行微观形貌特征分析,最后在单轴压缩力学试验结果的基础上,分析早期水化反应进程及产物对充填体强度演化的影响。研究表明,灰砂比越大,水化放热速率及放热量越大,生成水化产物越多,体积电阻率越大。同时水化反应速率直接决定了充填体自身强度形成的快慢,生成的Ca(OH)2减小了料浆体积电阻率,加快充填体自身强度的增长;随后生成的钙矾石(Aft)导致颗粒间孔隙更加致密,抑制了离子的溶解,减缓放出热量速率,从而阻碍了充填体强度的增长;当水化反应进行14 d基本结束后,充填材料凝结固化成为一个整体,强度基本稳定。充填体强度的变化呈现先迅速增加随后增加趋势逐渐减小直至稳定的趋势,为矿山采用分级细尾砂进行井下采空区充填、控制深部采场温度提供理论支撑及科学指导。

     

    Abstract: In this work, the early hydration reaction and mechanical evolution characteristics of graded fine tailing cemented backfill are studied. The hydration exothermicity and electrical resistance characteristics of backfill slurry with different lime sand ratios are tested, and the microscopic morphology characteristics of early hydration products are analyzed according to scanning electron microscopy (SEM). Finally, on the basis of uniaxial compression mechanical test results, the early hydration reaction process and the effect of the products on the strength evolution of the backfill are analyzed. The results showed that the exothermic process of slurry hydration underwent rapid reaction stage I, induction stage II, acceleration stage III, deceleration stage IV, and stabilization stage V. The volume resistivity underwent increasing stage I, decreasing stage II, and accelerated increasing stages III. The slurry lime sand ratio affects the hydration heat release and volume resistivity. The larger ratio is, the greater the hydration heat release rate and heat release, the more hydration products are generated, and the greater the volume resistivity. An increase in the lime sand ratio prolongs the induction time of the hydration reaction and increases the rate of the hydration reaction during the induction period. At the same time, it retards the growth of volume resistivity. The larger the lime sand ratio is, the stronger the retarding effect and the larger the retarding effect on the growth of slurry volume resistivity. The rate of the hydration reaction directly determines the formation speed of the backfill strength. When the main components of the filling material, C3S and C3A, are dissolved rapidly in water, much heat is released. The generated Ca(OH)2 reduces the volume resistivity of the slurry and accelerates the growth of the backfill strength; the AFt generated subsequently compacts the pores between particles, blocks the dissolution of ions, decreases the rate of heat release, and prevents the growth of backfill strength. The backfill strength increases rapidly from 0–3 d and slowly from 3–7 d. When the hydration reaction is basically completed after 14 d, the filling material is solidified overall, and its strength is basically stable. The change in backfill strength first increases and then gradually decreases until stabilizing. These research conclusions provide theoretical support and scientific guidance for mining to adopt graded fine tailings to fill the underground goaf and control the temperature of the deep stope.

     

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