ISSN 1000-3665 CN 11-2202/P

    考虑损伤和硬化的岩石单轴加速蠕变本构模型

    Uniaxial accelerated creep constitutive model of rock considering damage and hardening

    • 摘要: 针对当前岩石蠕变研究中对非线性特征、加速蠕变变形规律理解与描述不足,以及现有模型难以全面反映蠕变过程中损伤与硬化耦合效应的问题,基于Rabotnov蠕变损伤法则,结合硬化与损伤理论,通过理论推导与模型验证相结合的方式,构建了考虑损伤和硬化双重效应的单轴加速蠕变本构模型。结果显示,破坏应力下岩石损伤变量随时间呈现出缓慢增长-陡然激增且接近破坏时趋近于1的特征,硬化函数验证了稳定阶段硬化现象的客观性,模型能准确描述不同应力下蠕变行为(相关性系数高于0.90)且对破坏应力下变形规律预测良好;该模型能有效弥补现有模型不足。研究成果可为理解岩石蠕变关键规律提供可靠理论工具,对地下工程围岩稳定评估及地质灾害防治有重要实际价值。

       

      Abstract: In view of the lack of understanding and description of nonlinear characteristics and accelerated creep deformation law in current rock creep research, and the difficulty of existing models to fully reflect the coupling effect of damage and hardening in creep process, this study aims to construct a creep constitutive model that can accurately describe these complex mechanisms to support the stability control of surrounding rock and the prevention and control of geological disasters in underground engineering. Based on Rabotnov creep damage law, combined with hardening and damage theory, a uniaxial accelerated creep constitutive model considering the dual effects of damage and hardening was constructed by combining theoretical derivation with model verification. The results show that the damage variable of rock under failure stress increases slowly with time-suddenly increases and approaches to 1 when it is close to failure. The hardening function verifies the objectivity of the hardening phenomenon in the stable stage. The model can accurately describe the creep behavior under different stresses (the correlation coefficient is higher than 0.90) and predict the deformation law under failure stress well. Finally, it is concluded that the model can effectively make up for the shortcomings of the existing model. It provides a reliable theoretical tool for understanding the key laws of rock creep, and also has important practical value for the stability evaluation of surrounding rock in underground engineering and the prevention and control of geological disasters.

       

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