单轴加载状态下岩石多参数损伤本构模型研究

基于单轴压缩声发射实验,以加载中岩石的声发射和塑性体积应变为损伤变量,建立一个多参数损伤本构模型,研究了岩石的损伤演变规律。研究表明,岩石损伤本构模型和试验应力应变曲线能很好地吻合,峰值强度之前理论值略大,峰值强度之后理论值下降较快;岩石损伤随轴向应变的增加而增大,峰值强度之前岩石损伤随加载而增加,峰值强度之后岩石轴向应力减小而损伤增加;该损伤本构模型获取的应力应变曲线和损伤值能综合体现岩石的声发射和塑性体积应变的发展。

Multiparameter Constitutive Model of Rock Damage under Uniaxial Loading

Based on acoustic emission test under uniaxial loading, a constitutive model of multiparameter damage is set up with acoustic emission and plastic volumetric strain serving as damage variable,and the rock’s damage trend is studied. The results are as following: Firstly, constitutive model of rock damage is accordant with testing result well. Before peak strength the theoretical results are bigger than testing results, and then the theoretical results decrease faster. Rock’s damage is keeping increasing when rock’s axial strain is increasing. Before reaching rock’s peak strength, its damage is keeping increasing with axial stress increasing, but behind rock’s peak strength, when axial stress decreases rock’s damage keep increasing. The rock’s stress-strain curve and damage, obtained from multiparameter constitutive model of damage, can embody the trend of acoustic emission and plastic volumetric strain.