充填体声发射分形特征及损伤演化试验研究

Experimental study on fractal characteristics and damage evolution of filling acoustic emission

为探究不同配比胶结充填体声发射分形特征与损伤演化间的耦合关系,量化分析充填体损伤度,本文开展了胶结充填体试样的单轴压缩声发射试验。通过比对剖析声发射信号分形特征,归纳出各配比充填体的破坏形式,并拟合各破坏类型充填体的声发射累计能率曲线,推导其与应变的耦合关系,借助连续损伤力学及数理统计理论建立基于累计声发射能率的损伤本构方程,并对其进行验证。研究表明,充填体的声发射特征与应力一应变力学响应具有密切联系,其损伤破坏都是从整体无序逐渐向局部有序发展的。随着灰砂比不断减小,充填体的破坏模式逐渐从脆性向延性转化发展。通过试验验证,不同破坏类型充填体分别建立的损伤本构方程准确度较高,可实现充填体的损伤量化计算。

In order to study the coupling relationship between the fractal characteristics and the damage evolution of acoustic emission for cemented filling body with different ratio of tailings,and to quantitatively analyze the damage degree o￡filling body,the uniaxial compression acoustic emission test of stope filling sample has been carried out.By comparing and analyzing the fractal characteristics of acoustic emission signals,the failure forms of each proportion filling body are summed up,the curve of acoustical emission accumulative energy rate of each failure type filling body is fitted,and the coupling relation with strain is deduced.Based on the theory of continuous damage mechanics and mathematical statistics,the damage constitutive equation based on accumulative acoustic emission rate is established and verified・The results show that the acoustic emission characteristics of stope filling body are closely related to the stress-strain response,and the damage of the stope filling body develops from the global disorder to the local order gradually.With the decrease of the ratio of ash to sand,the failure mode of the filling body gradually changes from brittleness to ductility.The experimental results verify that the damage constitutive equations established by different failure types of backfill are accurate and can be used to calculate the damage of backfill and provide a theoretical basis for damage assessment of backfill。