LI Tie, LI Kexuan, PI Xiyu, FANG Chuang. Time-dependent behavior of acoustic emission feature parameters of sandstone under bending load[J]. Journal of China Coal Society, 2018, (11). DOI: 10.13225/j.cnki.jccs.2018.0055
Citation: LI Tie, LI Kexuan, PI Xiyu, FANG Chuang. Time-dependent behavior of acoustic emission feature parameters of sandstone under bending load[J]. Journal of China Coal Society, 2018, (11). DOI: 10.13225/j.cnki.jccs.2018.0055

Time-dependent behavior of acoustic emission feature parameters of sandstone under bending load

  • In order to explore the mechanical mechanism influence of mining rate on the characteristics of roof breaking in goaf,with different loading rates,a three point bending test of sandstone and acoustic emission testing was carried out to study the mechanical behaviour of bending fracture process of sandstone and the time effect by the loading rate and fracture precursor characteristics. The results show that the faster the loading rate is,the higher the stress condition of the significant initial damage acoustic emission is,and the higher the strain energy is. Before the rock breaks,the precursory AE time length is negatively correlated with the loading rate. The precursory AE time is shortened as load-ing rate increases,and its predictability is the worst. The loading rate is positively correlated with the peak AE energy and the failure load,which is negatively correlated with the peak value of AE counts. The faster loading rate is,the lar-ger failure load energy is,the fewer the peak AE counts,and the higher the energy is released at one time. The above acoustic emission feature parameters of the rock are the function of loading rate,and time-dependent. This paper ex-plains the reason why the higher the mining speed is,the higher the hazard of roof dynamic disaster is and the worse the predictability is from its mechanism aspect.
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