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为了研究受载煤岩变形破裂过程中电磁辐射动态非线性特征,对不同力学性质的煤样进行了不同加载速率的单轴压缩实验和分级加载实验,发现受载煤体电磁辐射由煤的力学性质、应力水平及加载速率共同决定,煤的强度越高、加载速率或应力水平越大,电磁辐射非线性特征越明显.依据煤的力学性质,受载煤体在变形破裂过程中其破坏前兆信号可以划分为3种类型.应用时变多重分形理论分析了电磁辐射时间序列,结果表明煤岩破裂失稳之前多重分形参数Δαm随载荷的增加呈增大趋势,在破坏后期Δαm有一定程度降低.裂纹扩展越激烈,煤岩内部损伤程度越高,Δfm越小.Δαm,Δfm的动态变化可以用来评价煤岩变形破裂过程及破坏阶段.
In order to study the dynamic nonlinear characteristics of electromagnetic radiation during deformation and rupture of loaded coal, uniaxial compression experiments and graded loading experiments of different mechanical properties of coal samples under different loading rates were carried out. It was found that the electromagnetic radiation of loaded coal was controlled by the mechanics of coal Properties, stress level and loading rate, the higher the strength of coal, the greater the loading rate or stress level, the more obvious the nonlinear characteristics of electromagnetic radiation.According to the mechanical properties of coal, the pre-destruction precursor of the loaded coal in the process of deformation and rupture The signals can be divided into three types.The temporal variation of electromagnetic radiation is analyzed by using time-varying multifractal theory.The results show that the multiplicative fractal parameter Δαm increases with the increase of load before rupture of coal and rock, and decreases to a certain degree The more severe the crack propagation, the higher the internal damage degree of coal and rock, the smaller the Δfm.The dynamic changes of Δαm and Δfm can be used to evaluate the deformation and fracture process and the failure stage of coal and rock.