Assessing the overall instantaneous behavior and strength properties of jointed materials have been the subject of important investigations in the last decades, including phenomenological or micromechanics-based contributions. However, less attention has been dedicated to delayed component of deformation in such media. This issue is addressed in this paper, which is devoted to the formulation of a micromechanical approach to effective viscoelastic properties of jointed rocks with consideration of constituents aging. At the scale of representative elementary volume (REV), the joints are modeled as planar interfaces whose behavior is described by means of generalized viscoelastic state equations under normal and shear loading conditions. Closed-form expressions for the homogenized creep tensor are derived from solving an appropriate viscoelastic concentration problem stated on the REV. The local strain and displacement jump fields are analyzed by extending the concept of strain concentration to relate the components of joint displacement jump to macroscopic strain. Main features of the theoretical overall creep behavior, such as the anisotropy associated with the privileged joint orientations, are highlighted through explicit formulations in some particular configurations of the jointed medium. Finally, the ability of the approach to accurately reproduce the creep behavior of jointed media is assessed by comparison with experimental data as well as with finite element solutions derived in the context of multilayered stratified composite modeling.

在过去的几十年中，评估接合材料的整体瞬时行为和强度特性一直是重要的研究课题，包括基于现象学或基于微力学的贡献。但是，人们很少关注这种介质中变形的延迟分量。该问题在本文中得到解决，该论文致力于制定一种微机械方法来解决节理岩石的有效粘弹性，同时考虑了成分的时效。在代表性基本体积（REV）的尺度上，将接头建模为平面界面，其行为通过常规的粘弹性状态方程在正常和剪切载荷条件下进行描述。均质蠕变张量的闭式表达式是通过解决REV上说明的适当粘弹性浓度问题得出的。通过扩展应变集中的概念来分析局部应变和位移跃变场，以将关节位移跃变的分量与宏观应变相关联。理论上的整体蠕变行为的主要特征，例如与特权接头方向相关的各向异性，通过在接头介质的某些特定配置中的明确公式突出显示。最后，通过与实验数据以及在多层分层复合模型的背景下得出的有限元解决方案进行比较，评估了该方法精确再现节理介质蠕变行为的能力。