关键词: 本构模型, 强度特征, 损伤特征, 结构失稳, 材料失效

Abstract: Based on the statistical damage mechanics theory of Weibull distribution, the limitations of the traditional constitutive model for the initial state damage and the post-peak feature characterization are optimized; and the constitutive equation which can characterize the initial damage to the mechanical behavior is established. The constitutive equation determines the mechanical properties and damage state of key feature points in the whole stress-strain process of rock, and divides the damage process of rock damage into six damage stages, explaining the damage evolution in the whole stress-strain process of rock. Meanwhile, combining with RFPA-2D numerical simulation analysis, it is determined that the structural instability point of the rock mass on the post-peak curve is the peak strain (1.00-1.32) times; the damage threshold is about 0.4-0.6 and the damage initiation strength is about 15% of the peak intensity; and the structural surface penetration breaking strength is about 41% of the peak intensity. It is theoretically determined that the residual strength point strain is about 4 times the peak strain.

Key words: constitutive model, strength characteristics, damage characteristics, structural instability, material failure