为探究边坡失稳的内在致灾机理, 针对软弱夹层这一重要影响因素进行研究。以炭质泥页岩软弱夹层为主要研究对象, 进行炭质泥页岩的分级剪切蠕变试验, 揭示其蠕变规律, 确定了其不同法向应力水平下的长期强度。通过对传统Maxwell体进行改进, 将传统黏性元件替换为分数阶元件, 引入考虑时效损伤的黏塑性体, 建立考虑时效损伤的炭质泥页岩分数阶蠕变模型; 基于1stOpt软件中的优化Levenberg-Marquardt法对炭质泥页岩试验蠕变曲线进行拟合, 对模型的准确性进行了验证, 并对模型进行参数敏感性分析。研究结果表明: 与传统西原模型相比, 改进的模型对试验数据有更好的拟合度, 能够完整表征炭质泥页岩的减速、等速和加速蠕变阶段, 尤其与加速蠕变阶段蠕变曲线的表征高度吻合; 蠕变曲线变化由参数$ gamma 、A、nu $控制, 材料参数$ A、nu $反映了炭质泥页岩的物理力学强度。研究结果可为含炭质泥页岩软弱夹层的边坡稳定性分析提供一定的参考。

To investigate the intrinsic disaster-causing mechanism of slope instability, the weak interlayer, an important influencing factor, is studied. Taking charcoal mud shale with weak interlayer as the main research object, the graded shear creep test of charcoal mud shale was carried out to reveal its creep law and determine its long-term strength under different normal stress levels. By improving the traditional Maxwell body, replacing the traditional viscous element with a fractional-order element, and introducing a visco-plastic body considering aging damage, a fractional-order creep model of charcoal mud shale considering aging damage was established. Based on the optimized Levenberg-Marquardt method of 1stOpt software, the experimental creep curves of the charcoal mud shale were fitted, and the accuracy of the model was verified, and the model was subjected to parameter sensitivity analysis. The results show that the improved model has a better fit to the test data when compared with the traditional Nishihara model, and can completely characterize the decelerated, isotropic and accelerated creep stages of the carbonaceous mud shale, especially highly consistent with the characterization of creep curve in the accelerated creep stage. The variation of creep curves were controlled by parameters, while the material parameter reflects the physical and mechanical strength of the carbonaceous mud shale. The results of this paper can provide some theoretical basis for the slope stability analysis of the soft and weak interlayer containing carbonaceous mud shale.