深部岩石渐进破损本构模型及其应用

深部岩石力学特性的数理描述与深部岩体的灾害控制密切相关。从岩石破坏过程和破坏机制出发,将代表性体元(RVE)划分为弹性区及剪切局部化带两个部分;并把剪切局部化带内的变形过程抽象为胶结强度弱化及摩擦强度增强两个阶段,重点考虑了这两个阶段一前一后发挥作用的破坏本质;同时采用细观链式模型及均匀化方法将破坏过程的细观特征与宏观力学特性相结合,建立了岩石局部化渐进破损本构模型的理论公式。模型计算结果与Yumlu和Ozbay试验结果吻合较好,证明了所提出模型的正确性。通过变化模型中的参数,进一步对深部岩石的局部化渐进破坏特征进行了分析,揭示了试样呈现"尺寸效应"、"形状效应"、应变软化及II型应力-应变曲线的内在原因及影响因素。

RESEARCH ON PROGRESSIVE DAMAGE CONSTITUTIVE MODEL AND ITS APPLICATION TO DEEP ROCK

The disaster control of the deep rock is closely related to the constitutive model of the rock. Based on the failure process and failure mechanism of rock, the localized progressive damage constitutive model is developed. In this model, the representative volume element (RVE) is divided into the elastic zone and localized shear band, and the deformation process of the localized shear band is again separated into cohesion weakening and friction strengthening phases. The emphasis in establishing the model is placed on the failure essence of the rock, ie., the cohesion weakening and friction strengthening phases should be exerted in tandem. Moreover, the chain model in localized band and homogenization method are adopted to combine the meso characteristics with the macro mechanical properties in this localized progressive damage constitutive model. Furthermore, based on the experimental results of Yumlu & Ozbay, the localized progressive damage constitutive model is well validated. Finally, the localized progressive failure characteristics of the deep rock are analyzed by changing the model’s parameters. The intrinsic reasons and influence factors of "size effect", "shape effect", strain softeningphenomena and type II stress-strain curves are pointed out.