基于声发射特征的充填体损伤演化研究

为探究声发射信号与充填体细观破坏之间的关系,研究声发射特征振铃计数、能率和应力随时间的变化规律,进一步揭示充填体损伤演化过程,进行了全尾砂胶结充填体声发射特性力学实验。基于损伤力学理论并引入有效损伤率,得到基于声发射累积事件率的损伤变量,然后构建了充填体损伤本构方程。研究结果表明,声发射振铃计数和能率在不同受力阶段呈现不同变化,与充填体内部孔隙及裂纹损伤演化过程有密切关系。振铃计数在弹性阶段前期达到最大,屈服阶段逐渐降低至最小;有效损伤率值与理论峰值应力呈负相关;与实验峰值应力相比,理论峰值应力出现于应变较大处;充填体为高损伤介质,当有效损伤率取值趋近于1时,理论模型曲线与实验曲线变化趋势相同,可以较好的描述充填体应力应变关系。

On the Damage Evolution of Fillings Based on Acoustic Emission Characteristics

In order to investigate the relation between acoustic emission signals and mesoscopic damage of fillings,to investigate characteristics of acoustic emission counts,energy and stress variation with time,to further reveal the damage evolution process of fillings,mechanical experiment of acoustic emission characteristics of unclassified tailing cemented fillings was carried out.Introducing damage mechanics theory and effective damage ratio,the damage variable was obtained based on cumulative event ratio of acoustic emission;then,the constitutive equation of fillings damage was established.Experimental results show that acoustic emission counts and energy ratio vary on different stages in evolution progress and are closely related with the inner porosity and crack damage evolution process.On the early elastic stage,emission counts reach the maximum value,and then gradually reduce to the minimum on yield stage.There is a negative relation between the value of effective damage ratio and theoretical peak stress.Comparing with experimental stress peak value,the theoretical stress peak value appears at the location,where the strain is bigger.Filling is a high damage medium,when effective damage ratio is approaching 1,variation trend of theoretical model curve and experimental curve is similar,which indicates that this model is able to better describe stress-strain relation of fillings.