A Micromechanics-Based Elastoplastic Damage Model for Rocks with a Brittle-Ductile Transition in Mechanical Response

作者：Hu, Kun; Zhu, Qi-zhi^*; Chen, Liang; Shao, Jian-fu; Liu, Jian

来源：Rock Mechanics and Rock Engineering, 2018, 51(6): 1729-1737.

DOI：10.1007/s00603-018-1427-z

• Brittle-ductile transition
• Effect of confining pressure
• Critical damage
• Micromechanical model
• Quasi-brittle rocks

As confining pressure increases, crystalline rocks of moderate porosity usually undergo a transition in failure mode from localized brittle fracture to diffused damage and ductile failure. This transition has been widely reported experimentally for several decades; however, satisfactory modeling is still lacking. The present paper aims at modeling the brittle-ductile transition process of rocks under conventional triaxial compression. Based on quantitative analyses of experimental results, it is found that there is a quite satisfactory linearity between the axial inelastic strain at failure and the confining pressure prescribed. A micromechanics-based frictional damage model is then formulated using an associated plastic flow rule and a strain energy release rate-based damage criterion. The analytical solution to the strong plasticity-damage coupling problem is provided and applied to simulate the nonlinear mechanical behaviors of Tennessee marble, Indiana limestone and Jinping marble, each presenting a brittle-ductile transition in stress-strain curves.

• 出版日期2018-6
• 单位核工业北京地质研究院; 河海大学