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通过水泥胶结分级尾砂充填体单轴抗压声发射试验,研究分析了整个充填体压缩破坏过程中的声发射能率、声发射b值、声发射能率分形维数与时间的关系曲线。试验结果表明:加载初期的声发射活动并不明显,直到加载至应力峰值时,声发射活动显著增强。同时分析表明:声发射b值和声发射能率分形维数曲线呈现明显的波动性,破坏前其曲线均表现出上升趋势,临近破坏时声发射b值和声发射能率分形维数都下降到最低值。利用声发射b值和声发射能率分形维数能较好地描述充填体在单轴抗压破坏时裂隙的产生、扩展至完全破坏情况,将声发射b值和声发射能率分形维数两者结合作为现场监测充填体稳定性的指标,可为矿山现场安全监测提供比单一声发射参数更为有效的依据。最后根据声发射累计能率定义损伤变量,建立了充填体压缩破坏过程中的损伤演化方程,进而得到了单轴压缩条件下充填体的损伤本构模型。
Through the uniaxial compressive acoustic emission test of cemented tailings filler, the acoustic emission energy, the b value of acoustic emission and the fractal dimension of acoustic emission energy in the process of compressive failure were analyzed. The experimental results show that the acoustic emission activity at the initial stage of loading is not obvious, and the acoustic emission activity is significantly enhanced until the stress peak is loaded. At the same time, the analysis shows that the fractal dimension curves of acoustic emission b value and acoustic emission energy show obvious fluctuation, and their curves show an upward trend before destruction, and the values of acoustic emission b value and acoustic emission energy fractal dimension decrease to the lowest value. Using the b value of acoustic emission and the fractal dimension of acoustic emission energy can well describe the generation of fractures during uniaxial compression failure and extend to the complete destruction. The b value of acoustic emission and the fractal dimension of acoustic emission energy Combined with the field monitoring indicators for the stability of the filling body, the mine site safety monitoring can provide a more effective basis than the single acoustic emission parameters. Finally, the damage variables are defined according to the cumulative energy of acoustic emission, and the damage evolution equations are established during the process of compressive failure of the filling body. Then, the damage constitutive model of the filling body under uniaxial compression is obtained.