充填体失稳破坏前兆识别及破坏形式演化规律研究

Study on the precursory identification and the evolution law of the failure of filling body

为研究充填体失稳破坏过程中声发射信号时频特征及破坏形式,对不同灰砂比充填体试件开展单轴加载声发射试验。通过频谱分析技术,采用时频域结合对试验结果进行深入剖析。结果表明:不同灰砂比充填体失稳过程中低频带信号占比最大,高频带信号次之,中频带信号最少;峰值应力前,低频信号明显减少,中、高频信号明显增加这一特征可作为充填体失稳破坏的前兆信息;声发射参数RA和AF特征值在不同时刻的分布特征,揭示了破坏形式的演变过程,灰砂比1∶6时充填体在压密及弹性阶段以张拉破坏为主,塑性变形及峰后破坏阶段以剪切破坏为主,灰砂比1∶10时充填体破坏全过程以张拉破坏为主、剪切为辅,灰砂比1∶15时充填体破坏全过程以张拉破坏为主。试验结果对细观角度下研究充填体失稳破坏机制以及采场充填体失稳的预测具有重要意义。

In order to explore the time-frequency characteristics of acoustic emission signals and failure modes in the process of instability failure of filling body,uniaxial loading acoustic emission tests were carried out on filling body with different cement-sand ratios.With spectrum analysis technology,the experimental results were analyzed in depth by means of time-frequency domain analysis.The research results showed that:In the process of instability of filling body with different lime-sand ratios,the low frequency band signals took the largest proportion,the high frequency band signals took the second place,and the medium frequency ones took the least.Before the peak stress,the low-frequency signals decreased obviously,and the medium and high-frequency signals increased obviously,which could be used as the precursor information of instability and failure of filling body.The distribution characteristics of acoustic emission parameters RA and AF eigenvalues at different times revealed the evolution process of failure modes.Tensile failure is the main failure mode in compaction and elasticity stage of filling body with the lime-sand ratio of 1∶6.Shear failure is the main failure stage in plastic deformation and post-peak failure stage.Tensile failure was the main failure stage in the whole process of filling body with the lime-sand ratio of 1∶10,and shear was the auxiliary one.Tensile failure was the main failure stage in the whole process of filling body with a lime-sand ratio of 1∶15.The test results were of great significance to the study of the failure mechanism of filling body and the prediction of the instability of stope filling body from the mesoscopic perspective.