A damage constitutive model for intermittent jointed rocks under cyclic uniaxial compression
A damage constitutive model for intermittent jointed rocks under cyclic uniaxial compression
复制标题
断续节理岩单轴循环压缩损伤本构模型
DOI：
10.1016/j.ijrmms.2018.01.046
复制
发表时间：
2018-03-01
影响因子：
7.2
通讯作者：
Dai, Feng
中科院分区：
文献类型：
--
作者：
Liu, Yi;Dai, Feng
提出了描述断续节理岩石单轴循环压缩变形和强度特性的损伤本构模型。首先，基于Lemaitre应变等效假设，结合微裂纹的Weibull统计损伤模型和宏观节理的断裂力学模型，推导了断续节理岩石的耦合损伤张量。第二，具有内部变量的疲劳本构模型（即，不可逆塑性应变）来再现岩石在循环荷载作用下疲劳变形和强度的退化行为。最后，建立了具有明确物理意义的断续节理岩体单轴循环压缩损伤本构模型。该模型综合考虑了微裂纹和宏观节理的耦合损伤，同时考虑了节理的几何参数和力学特性。此外，该模型能够再现岩石材料在循环荷载作用下的滞回应力-应变曲线和累积疲劳塑性变形。此外，压实系数，这是定义为割线模量与杨氏模量的比值，提出了反映压实阶段的岩石材料在第一次加载过程中。为了验证这一新模型，进行了9个循环单轴压缩试验的完整和节理岩石样品制备的人造岩石类材料。循环应力-应变曲线和疲劳变形模量的理论和实验结果之间观察到合理的一致性。
A damage constitutive model is proposed to describe the deformation and strength characteristics of intermittent jointed rocks under cyclic uniaxial compression. First, a coupled damage tensor for intermittent jointed rocks is derived based on the Lemaitre strain equivalence hypothesis, which combines the Weibull statistical damage model for micro-flaws and the fracture mechanics model for macro-joints. Second, a fatigue constitutive model with an internal variable (i.e., irreversible plastic strain) is proposed to reproduce the degradation behaviors in fatigue deformation and strength of rocks under cyclic loading. Finally, a damage constitutive model with a definite physical significance is constructed for the intermittent jointed rocks under cyclic uniaxial compression. Our new model comprehensively reflects the coupled damage induced by micro-flaws and macro-joints, in which the geometric parameters and the mechanical properties of intermittent joints are considered simultaneously. Moreover, this model is able to reproduce the hysteretic stress-strain curves and the cumulative fatigue plastic deformation of rock materials under cyclic loading. In addition, a compaction coefficient, which is defined as the ratio of the secant modulus to the Young's modulus, is proposed to reflect the compaction stage of rock materials during the first loading process. To validate this new model, nine cyclic uniaxial compression tests are conducted on both intact and jointed rock samples prepared with synthetic rock-like materials. A reasonable consistency is observed between the theoretical and experimental results for the cyclic stress-strain curves and the fatigue deformation modulus.