本构模型是描述岩体变形破坏特性、表征其力学行为最有效的方法，针对岩石受荷过程中损伤速率变化建立动态损伤演化方程及本构模型成为岩体力学重要内容。

为进一步深入研究荷载作用下岩石变形破坏全过程，将受荷岩石抽象为损伤和未损伤2部分，且未损伤部分承担有效应力，损伤部分承担残余应力，基于动态损伤速率的演化特征，建立动态损伤演化方程及本构模型，通过红砂岩常规三轴压缩试验结果验证模型的合理性。

结果表明：模型理论曲线可较好地反映岩石受荷损伤破坏的力学行为，其动态损伤演化依次经过损伤不变、损伤加快扩展、损伤缓慢增加和完全损伤4个阶段，分别对应理论曲线的压密−弹性变形、塑性变形、峰后软化和残余变形阶段；随着围压的增加，岩石动态损伤累积速率减缓，说明围压可抑制损伤扩展，表现为岩石抗压强度的增加和塑性特性的渐次增强；最大损伤速率较为接近峰值点，并在其右侧应力下降阶段，且对应的损伤变量在不同围压下基本一致；模型参数f增加，岩石强度及塑性变形增加；模型参数m减小，岩石强度增加，但对岩石损伤变形影响较小。通过建立的演化方程及本构模型，探讨了最大损伤速率点的特征及模型参数对岩石强度和损伤变形的影响，对岩石力学的发展有重要的参考价值。

A constitutive model is identified as the most effective method for describing the deformations and failure characteristics of rocks and characterizing their mechanical behavior. Developing the equation and constitutive model for the dynamic damage evolution of rocks based on changes in their damage rates under loading is an important part of rock mechanics.

To further investigate the whole process of rock deformations and failure under loading, rocks were divided into the damaged and undamaged parts via abstraction, with the latter bearing effective stress and the former bearing residual stress. This study established the equation and constitutive model based on the evolutionary characteristics of the dynamic damage rate and verified the rationality of the model using conventional triaxial compression experiments on red sandstones. [Results and Conclusions] The results indicate that the theoretical curve derived from the model can effectively reflect the mechanical behavior of rock damage and failure under loading. The dynamic damage of rocks underwent four stages: unchanged damage, accelerated damage propagation, slowly increasing damage, and complete damage, which correspond to the compression and elastic deformation, plastic deformation, post-peak softening, and residual deformation stages of the theoretical curve, respectively. According to the curve, the cumulative dynamic damage rate of rocks slowed down with an increase in the confining pressure. This indicates that confining pressure can inhibit damage propagation, as manifested by an increase in the compressive strength of rocks and a gradual enhancement of their plastic properties. The maximum damage rate was present in the stress decrease stage to the right of the curve’s peak, approaching the peak. Furthermore, the damage variable corresponding to the maximum damage rate was roughly consistent under different confining pressures. An increase in model parameter f was associated with an increase in the strength and plastic deformation of rocks. In contrast, a decrease in model parameter m corresponded to an increase in the rock strength but had minor impacts on the damage and deformation of rocks. By establishing the equation and constitutive model for the dynamic damage evolution of rocks, this study explores the characteristics of the maximum damage rate and the impacts of the model parameters on rock strength and the damage and deformation of rocks, serving as a valuable reference for the development of rock mechanics.