尾砂胶结充填体声发射特征的分形分析

On the Characteristics of Acoustic Emission of Cemented Tailings Fill Based on Fractal Theory

对取自某铜矿的尾砂按不同配比制备尾砂胶结充填体试样,在单轴压缩条件下,进行尾砂胶结充填体破坏全过程声发射试验,通过对声发射基本参数序列进行理论分析,证实了充填体的声发射过程具有分形特征,并采用"G-P算法"计算了能率时间序列的关联维数.结果表明:低配比(1∶8)试样的关联维数在应力水平为60%时突降到最低,结构内部裂纹扩展开始变得有序,并呈宏观态势发展;高配比(1∶4)试样的关联维数是逐渐降低的,在峰值破坏时降到最小.此外,关联维数的"突降→平静"和"持续降低"两种模式可分别作为两种配比的充填体现场稳定性监测、预报的前兆判据.

Cemented tailings backfill samples were produced with tailings from a a copper mine by different ratios.Experimental tests were performed on the cemented tailings backfill samples for the characteristics of acoustic emission（AE） under the condition of uniaxial compression.The testing results confirmed that the AE series is of fractal characteristics upon theoretical analysis on the basic parameters of AE.G-P algorithm worked out the correlation dimension of AE.The correlation dimension of low ratio（1∶8） samples reduced to the minimum when the stress level increases to 60 %.Most of the micro-cracks begin an orderly expansion and rapidly increases.The correlation dimension of the high ratio（1∶4） samples gradually reduces to the minimum when the samples start to break down.The dump-quiet period model and long-term decline model can be used as the precursor criterion for monitoring and forecasting of the stability of backfill.