沿空留巷高水充填材料改性试验及工程应用

为解决原有高水材料存在韧性差、可收缩量小等问题,通过分析现场充填体破坏特征,运用"让抗"支护机理将充填体划分为充填体层和让压层,采用正交配比试验对高水材料性能缺陷进行改进,并对改性前后的材料固结体进行微观对比分析。同时采用施加不同支护的方式模拟试验得到充填体在侧向约束条件下最优支护条件。试验结果表明:改性后的高水材料充填层28 d强度达到12.18 MPa,让压接顶层膨胀率为9.60%,引入发泡剂、纤维等外部添加物剂对材料生成钙矾石等水化产物无影响,侧向约束条件下最优支护组合表面位移仅占试样宽度的3.65%。最后,将改性后的高水材料应用现场,现场试验结果表明:充填体侧表面位移仅为229 mm,顶板下沉量控制在216 mm左右,改性后的高水材料能够很好地满足沿空留巷要求。

Modification test and engineering application of high-water filling material in gob-side entry retaining

This paper aims to solve the poor toughness, small compressibility of high-water material. Based on the analysis of the failure characteristics of the backfilling body, the roadside backfilling body was divided into the yieldlayer and the support layer by the "yielding resistance" supporting mechanism. Orthogonal method was adopted to improve the high-water material performance, and the microstructure of the consolidated material before and after modification was compared. At the same time, simulation tests were conducted to obtain the optimal supporting conditions and material mechanical properties of backfilling body under lateral constraint conditions. The results showed that foaming agents and fibers had no effect on the formation of ettringite and other hydration products.The 28 days strength of the improved support layer consolidate body reached 12.18 MPa and the expansion rate of the yielding layer was 9.60%.The surface displacement of the optimal support combination under lateral constraint was 3.65%. The following industrial test indicated that the lateral surface displacement of filling body was only 229 mm, and the roof subsidence was controlled at about 216 mm. The high water material after modification can well meet the requirements of gob-side entry retaining.