基于表面分形特征的煤岩冲击倾向性评价

对于煤岩体冲击倾向性的评价,目前主要采用煤的冲击能量指数K_E,弹性能量指数W_ET和动态破坏时间D_t三种指标。由于煤岩体的孔隙越发育(也就是孔隙率大、孔隙数量多、结构复杂等),则一般情况下其宏观力学强度就越低,岩体内积聚的能量容易通过塑性变形或破裂消耗掉,冲击倾向性就越低;同时,通过研究煤岩扫描电镜(SEM)图像,计算其孔隙特征参数和分形维数,发现煤岩体具有良好的分形特征,并且孔隙发育程度可以很好地被分形维数所描述,因此引入分形维数D_f来描述煤岩冲击倾向性是合适的,一般来说分形维数越大则冲击倾向性越小。

Evaluating the Proneness of Coal Rockburst Based on the Surface Fractal Feature

Currently, there are three major indexes applied in evaluating proneness of the coal rockburst, including impact energy index K_E,elastic energy index W_ET, and dynamic failure time D_t. In general case, the more complicated the porosity of coal rock is, that is, higher porosity, more pores, more complicated structure, etc., the greater the attenuation of the mechanical strength will be, and the easier the consumption of energy, accumulated in the coal rock, will be consumed away by means of plastic deformation or rupture, therefore the less the proneness of impact will be; meanwhile, by studying coal rock image taken by scanning electron microscopy (SEM) to calculate the pore characteristic parameters and the fractal dimension, it is found that coal-rock mass has good fractal characteristics, and that the pore development can be well demonstrated by fractal dimension. Therefore, in addition to the three indexes, the fractal dimension D_f also can be introduced to evaluate the proneness of the coal rockburst based on the above research, and the conclusion can be drawn that the greater the fractal dimension, the less the proneness of coal rockburst will be.