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Abstract：
Polypropylene fiber was equally mixed into alkali-activated slag fly ash geopolymer in order to ensure the filling effect of mine goaf and improve the stability of cemented gangue paste filling material with ecological matrix. Triaxial compression tests were then conducted under various conditions. The mechanical properties and damage characteristics of composite paste filling materials are studied, and the damage evolution model of paste filling materials under triaxial compression is established, based on the deviatoric stress-strain curve generated by the progressive failure behavior of samples. Internal physical and chemical mechanisms of the evolution of structure and characteristics are elucidated and comprehended via the use of SEM-EDS and XRD micro-techniques. The results show that the fiber can effectively improve the ultimate strength and the corresponding effective stress strength index of the sample within the scope of the experimental study. The best strengthening effect is achieved when the amount of NaOH is 3% of the mass of the solid material, the amount of fiber is 5‰ of the mass of the solid material, and the length of the fiber is about 12 mm. The action mode of the fiber in the sample is mainly divided into single-grip anchoring and three-dimensional mesh traction. As the crack initiates and develops, connection occurs in the matrix, where the fiber has an obvious interference and retardation effect on the crack propagation, thereby transforming the brittle failure into a ductile failure and consequently improving the fracture properties of the ecological cementitious coal gangue matrix. The theoretical damage evolution model of a segmented filling body is constructed by taking the initial compaction stage end point as the critical point, and the curve of the damage evolution model of the specimen under different conditions is obtained. The theoretical model is verified by the results from the triaxial compression test. We concluded that the experimental curve is in good agreement with the theoretical curve. Therefore, the established theoretical model has a certain reference value for the analysis and evaluation of the mechanical properties of paste filling materials. The research results can improve the utilization rate of solid waste resources.
摘要：
为保证矿山采空区的充填效果,提高生态基质胶结煤矸石膏体充填材料的稳定性,将聚丙烯纤维均匀掺入到碱活化矿渣粉煤灰地聚合物中。然后在各种条件下进行三轴压缩试验。研究了复合膏体充填材料的力学性能和损伤特性,建立了膏体充填材料在三轴压缩作用下的损伤演化模型,基于样品渐进破坏行为产生的偏应力-应变曲线。通过使用SEM-EDS和XRD微观技术阐明和理解了结构和特征演变的内部物理和化学机理。结果表明,在试验研究范围内,纤维能有效提高试样的极限强度和相应的有效应力强度指标。当NaOH用量为固体材料质量的3%时，强化效果最佳，纤维的量为固体材料质量的5‰，纤维的长度约为12mm。样品中纤维的作用方式主要分为单握锚固和三维网状牵引。随着裂缝的开始和发展，连接发生在矩阵中，其中光纤对裂纹扩展有明显的干扰和延迟效应，从而将脆性破坏转化为延性破坏，从而改善生态胶凝煤矸石基质的断裂性能。以初始压实阶段终点为临界点,构建分段充填体损伤演化理论模型,得到了不同条件下试样的损伤演化模型曲线。三轴压缩试验结果验证了理论模型的正确性。我们得出结论，实验曲线与理论曲线吻合良好。因此,所建立的理论模型对膏体充填材料力学性能的分析与评价具有一定的参考价值。研究结果可以提高固体废物资源的利用率。
