岩石单轴压缩蠕变损伤本构模型

A Uniaxial Compression Creep Damage Constitutive Model for Rock

准确预测岩石蠕变行为对岩石力学与工程的研究具有非常重要的意义。首先对岩石蠕变机理及典型蠕变曲线进行了分析,其次通过在经典岩石蠕变模型如J体模型的基础上引入损伤理论及Kachanov损伤演化定律,进而建立了一个新的岩石蠕变损伤本构模型。第三,对模型参数的确定方法进行了详细的研究。最后,引用其他学者所开展的不同轴压下岩石单轴压缩蠕变试验对该模型的合理性进行了验证。可以发现本文所提出的模型不仅能够很好地预测岩石的稳定蠕变阶段,而且还能预测经典模型所不能反映的岩石加速蠕变变形。结果表明损伤理论能够很好地反映岩石的蠕变破坏机理,为了能够准确模拟岩石蠕变变形全过程,在经典的J体模型中引入损伤因子是很有必要的。

Accurate prediction of rock creep behavior is of great significance to rock mechanics and engineering.In this study,the creep mechanism of rock and the typical creep deformation curve are firstly analyzed.Then,a new creep damage constitutive model for rock is established by introducing the damage theory and Kachanov damage evolution law into the classic creep constitutive model such as the J body model.Thirdly,the determination method of the model parameters is studied in detail.Finally,uniaxial creep tests under different axial stress conditions reported by other researchers are adopted to validate the proposed model.It is found that the proposed model can predict not only the steady creep deformation but also the accelerating creep deformation that classical models fail to reproduce.It can be concluded that the damage theory is capable of capturing the rock creep failure mechanism,and the introduction of damage factor into the classical model such as J body model is essential to accurately predict the full creep stage of a rock.