Laboratory study and constitutive modeling of time-dependent properties of a naturally filled discontinuity
Laboratory study and constitutive modeling of time-dependent properties of a naturally filled discontinuity
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DOI：
10.1007/s40948-023-00640-1
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发表时间：
2023-07
影响因子：
5
通讯作者：
Sheng Zhang;Yan Zheng;C. Jia;Ming-feng Lei;Zhong Li
中科院分区：
文献类型：
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作者：
Sheng Zhang;Yan Zheng;C. Jia;Ming-feng Lei;Zhong Li
天然充填结构面的时变特性是保证隧道长期稳定性的关键。本研究发展了一种新的取样方法来制备天然填充结构面样品，然后在不同的正应力下进行剪切蠕变试验。详细分析了蠕变变形、瞬时变形、稳态蠕变速率和长期强度等随时间变化的特性。结果表明，随着剪切应力的增大，累积蠕变量和稳态蠕变速率均呈指数增长。值得注意的是，在较低的法向应力（0.2 MPa），局部压实和旋转的石料颗粒内的填料的不连续性样品导致蠕变变形的减少。在此基础上，提出了一种基于Kachanov-Rabotnov蠕变损伤理论的新型流变单元。将该非线性单元与经典的Burgers模型串联，建立了一个描述天然充填结构面蠕变三阶段的本构蠕变模型。本文所提供的试验数据和所建立的蠕变模型，可为确保穿越结构面隧道的长期稳定性和安全性提供有价值的参考。
Time-dependent properties of naturally filled discontinuities play a critical role in ensuring the long-term stability of tunnels. This study developed a novel sampling method to prepare samples of naturally filled discontinuities, which were then subjected to shear creep tests under varying normal stresses. The time-dependent properties, including creep deformation, instantaneous deformation, steady-state creep rate, and long-term strength, were carefully analyzed. The results showed an exponential increase in cumulative creep deformation and steady-state creep rate with the augmentation of shear stress. Notably, under lower normal stress (0.2 MPa), the local compaction and rotation of stone particles within the fillers of the discontinuity samples lead to a reduction in creep deformation. Drawing on the experimental results, a new rheological element based on the Kachanov–Rabotnov creep damage theory was proposed. By incorporating this nonlinear element in series with the classical Burgers model, a constitutive creep model was established to describe the three creep stages of naturally filled discontinuities. The presented experimental data, and the developed creep model, can serve as valuable references for ensuring the long-term stability and safety of tunnels traversing through discontinuities.