岩石塑性应变损伤模型的建立及应用

Development of a Model for Rock Damage Caused by Plastic Strain and Its Application

岩石塑性变形和损伤变量的微观机制都是岩石中微裂纹的萌生和发育,塑性变形与损伤在岩石材料中是同时出现的,它们的演化规律是相互耦合的。本文采用基于塑性应变的损伤变量,定义岩石在破坏过程中塑性应变增量与损伤增量成正比关系,并把极限塑性应变归一于岩石的临界损伤值,建立了岩石塑性应变损伤模型和本构模型。实验曲线与利用所建立的塑性应变损伤模型计算的应力-应变曲线吻合较好,岩石塑性应变损伤模型能较好地描述岩石整个加载过程中的损伤与应力、应变的关系。并根据岩石塑性应变损伤模型,分析了单轴压缩荷载作用下岩石的应力和应变与损伤的演化规律。

The microcosmic mechanism of rock＇s plastic deformation and damage variables is microcosmic crack＇s bud and development of rock. Therefore plastic deformation and damage come forth at the same time and their evolving rule is coupled each other. Rock＇s plastic strain serves as damage variable and direct-ratio relation of rock＇s plastic strain and damage is defined. Rock＇s critical damage and critical strain are related by normalization method. Then rock＇s plastic strain damage model and constitutive model are set up. By comparing the stress-strain curve obtained from the test with the theoretical stress-strain curve attained from a plastic stain damage model, a conclusion comes out clear that the theory is consistent with tested datum. It is shown that the rock＇s plastic strain damage model is suitable for the description and analysis of the relationship between the damage and stress or strain during loading process. By using rock＇s plastic strain damage model and tested datum, the relation between rock＇s damage and stress, damage and strain can be analyzed.