刀具压入破岩声发射分形特征实验

Experimental Research on Fractal Characteristics of Acoustic Emission during Cutter Pressing in Rock Fragmentation

选用一字型刀具对花岗岩进行静力破碎实验,采用AEwin-USB型声发射信号采集系统采集声发射信号,应用分形理论分析不同加载速率下声发射分形特性.结果表明,随着加载速率的增加,刀具破岩程度愈显剧烈,且伴随着的声发射信号更强;声发射振铃计数率、能量率曲线能够很好描述刀具破岩过程;刀具破岩过程中声发射参数序列具有分形特征,且分形维数随加载速率的增大而逐渐减小;声发射分形维数随时间变化规律很好地反映了刀具破岩是一个降维有序、耗散结构的过程;刀具破岩声发射序列分维曲线呈一个波动上升→持续降低直到最低的变化规律,可以将分形维数持续降低作为岩石破坏失稳的前兆依据.

The normal cutter was applied to conduct rock static breaking test on granite. Using AEwin-USB type acoustic emission signal acquisition system to collection AE signal,fractal characteristics of AE under different loading rate was analyzed by fractal theory. The results show that the normal cutter crushes rock more intense and accompanied by acoustic emission signal is stronger with the increase of loading rate. Acoustic emission ring count rate,energy rate curve well describe the whole process of rock breaking tool. Acoustic emission parameters sequence during the process of rock breaking tool has fractal characteristics,and the fractal dimension of AE is gradually reduced with the increased loading rate. The fractal dimension of AE reflected the whole process of rock breaking tool which is a dimensionality reduction ordered,dissipative structure process variation with time. The fractal dimension curve of AE sequence is a rising volatility→continue to reduce until the lowest variation. The descent of the fractal dimension can be regarded as the precursor information to predict the collapse of the rock masses.