关键词: 工程岩石类材料, 刚性试验机, 材料稳定性, 材料不稳定性, 刚度劣化, 弹塑性耦合理论, 塑性势理论, Drucker-Prager准则

Abstract: Based on non-associative flow theory and elasto-plastic coupling theory, the instability of engineering rock-like materials was investigated. Due to the stiffness deterioration properties of engineering rock-like materials, material instabilities may occur in softening plastic, perfectly plastic and low hardening plastic phases. For the elasto-plastic coupling theory, positive definiteness of the elasto-plastic coupling constitutive matrix was discussed, and the condition of material instability was obtained. For the plastic potential theory, symmetric part of the constitutive matrix was used for material stability analysis and same results could be obtained.

Key words: engineering rock-like materials, stiff testing machine, material stability, material instability, stiffness deterioration, elasto-plastic coupling theory, plastic potential theory, Drucker-Prager criterion