为探究煤矸石混凝土力学特性,开展了煤矸石混凝土的多相细观力学特性试验研究,并基于细观尺度建立了煤矸石混凝土非均质数值模型,研究了煤矸石混凝土内部各种介质对煤矸石混凝土力学性能的影响。结果表明:细观模型能较好地描述煤矸石混凝土的力学特性、破坏模式和内部损伤演化过程;煤矸石混凝土的力学特性与三相力学性能有关,随着ITZ强度的增加,煤矸石混凝土的峰值应力先增大后减小,但残余强度趋于一致。改善ITZ力学特性对煤矸石混凝土的破坏模式及宏观裂缝的分布和扩展影响不大;提高水泥砂浆强度可以提高煤矸石混凝土的峰值应力和脆性;粗骨料强度提高了混凝土的峰值应力。当σcp-Agg<σcp-M时,可有效提高混凝土的峰值应力;当σcp-M<σcp-Agg时,峰值应力增长率迅速下降。增加骨料的强度可以改善混凝土的脆性。

In order to investigate the mechanical properties of coal gangue concrete, the multiphase micromechanical properties of coal gangue concrete were studied. Based on the meso-scale, the heterogeneous numerical model of gangue concrete was established, and the influence of various internal media on the mechanical properties of gangue concrete was analyzed. The results show that the mesoscopic model can well describe the mechanical properties, failure mode and internal damage evolution process of gangue concrete; The mechanical properties of gangue concrete are related to the three-phase mechanical properties; With the increase of ITZ strength, the peak stress of gangue concrete first increases and then decreases, but the residual strength tends to be the same; The improvement of ITZ mechanical properties has little effect on the failure mode of gangue concrete and the distribution and propagation of macro-cracks; Increasing the strength of cement mortar can increase the peak stress and brittleness of coal gangue concrete; The strength of coarse aggregate increases the peak stress of concrete; When, the peak stress of concrete can be effectively increased; When, the peak stress growth rate decreases rapidly; The brittleness of concrete can be improved by increasing the strength of aggregate.