散体充填材料压实力学特性的宏细观研究

为提高西部矿区散体充填材料的抗压性能，采用扫描电子显微镜技术、图像处理技术以及颗粒流数值模拟相结合的方法，研究散体充填材料的细观参数与宏观应变量之间的关系。通过选取颗粒等效粒径、颗粒形状系数、颗粒定向度、表观孔隙率、连通率和颗粒接触关系等6个指标对散体充填材料的形态特征、孔隙特征、接触特征进行了细观量化分析；通过PFC数值模拟对散体充填材料细观参数与宏观压实力学特性的相关性进行了模拟研究，结果表明：颗粒摩擦因数和颗粒孔隙率是散体充填材料宏观应变量的主控参数。基于西部矿区散体充填材料的细观结构，从减少充填材料孔隙率和增大充填材料摩擦性两方面出发，对其进行优化，并将优化后的散体充填材料在陕北常兴煤矿3101工作面进行工业性试验，实测地表最大下沉量为15 mm，最大水平变形为0.8 mm/m，地表沉陷得到有效控制。

Macro-micro research on compaction properties of granular backfilling materials

To improve the compaction properties of granular backfilling materials in western mining area，this paper analyzed the relationship between micro-parameters and macroscopic-strain of granular backfilling materials using the methods of scanning electron microscopy，image processing and particle flow numerical simulation.By selecting six indicators such as the equivalent grain size of particles，particle shape coefficient，the degree of particle orientation，apparent porosity，connectivity rate and grain contact relations，the morphological characteristics，pore characteristics and contact characteristics of granular backfilling materials were quantitatively analyzed.Through PFC numerical simulation，the relationship between micro parameters and the compaction properties of granular backfilling materials was discussed，and the result shows that the friction coefficients and the porosity of particles are the main control parameters of the macroscopic strain of granular backfilling materials.From the perspective of reducing the porosity of backfilling materials and increasing the friction of backfilling materials，the granular backfilling materials in western mining area were optimized on the basis of its meso structure and the optimized granular backfilling materials were used in the 3101 working face of Changxing coal mine，the result indicates that the maximum displacement of surface is 15 mm，the maximum horizontal deformation is 0.8 mm/m，and the surface subsidence is controlled effectively.