Avalanches in Compressed Sandstone: Crackling Noise under Confinement

Crystals

EkhardK.H. Salje¹  Hanlong Liu²  Yunfeng Zhao²  Xiang Jiang²  Kainan Xie³ 

[1] Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK;School of Civil Engineering, Chongqing University, Chongqing 400044, China;State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China;

关键词: sandstone;    acoustic emission;    crackling noise;    mean-field model;   

DOI  :  10.3390/cryst9110582

来源: DOAJ

【 摘 要 】

The acoustic emission, AE, from avalanches of local cracks and microstructural changes of sandstone under confined compression have been reported. These avalanches soften the underlying minerals and play a key role as indicators for the prediction of geo-engineering disasters, such as mining collapses, rock outbursts caused by high ground stress, and man-made quakes by fracking. Compressed sandstone is a model material for the investigation of avalanches. The avalanche energies, amplitudes, and waiting times show the probability distributions that allow us to distinguish between three compression stages; namely, (I) pre-failure, (II) correlated failure, and (III) post-failure. The energy of stage I and stage II is power-law distributed and scale invariant, while post-failure experiments show power laws with high exponential damping (friction). The scaling behavior is close to the predictions of a mean-field (MF) model (stage II) and a force-integrated mean-field model (stage I). Confinement shifts the value of the energy exponent closer to the MF prediction. Omori’s law and waiting time distributions are independent of stress during the compression; their scaling exponents are very similar to those found in seismological studies.

【 授权许可】

Unknown