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岩石具有重要的不可忽略的黏滞特性,准静态条件下试样应力–应变曲线表现出明显的加载速率相关特性,宏观表现为试样加卸载过程中的弹性后效,弹性蠕变和松弛等非平衡态非线性效应。基于经典的PreisachMayergoyz空间理论模型,引入具有时间依赖性的滞弹细观单元,得到改进的PM空间理论模型。采用所提出的改进的PM空间模型,研究不同加载速率下试样应力–应变曲线关系特征,以及准静态条件下试样加载过程中的非平衡效应。最后,提出滞弹细观单元变形–时间曲线的试验获取方法以及改进PM空间的重构方式。研究结果表明,加载速率越小,试样滞回曲线所围成的面积越小;加载速率越大,试样达到平衡状态所需要的时间越长。
The rock has important non-negligible viscous properties. The stress-strain curves of the specimens show obvious loading rate-dependent properties under quasi-static conditions. The macroscopic appearances are elastic aftershock, elastic creep and relaxation Non-equilibrium nonlinear effects. Based on the classical theory of Preisach Mayergoyz space, a time-dependent viscoelastic meso-element is introduced to improve the theoretical model of PM space. The improved PM space model is used to study the relationship between stress-strain curves and stress-strain curves at different loading rates, as well as the non-equilibrium effect of the specimen during quasi-static loading. Finally, the method of obtaining the deformation-time curve of the viscoelastic meso-unit and the reconstruction method of improving the PM space are proposed. The results show that the smaller the loading rate is, the smaller the area enclosed by the sample hysteresis curve is. The larger the loading rate is, the longer the sample needs to reach the equilibrium state.