Geotechnical stability analysis considering strain softening using micro-polar continuum finite element method

基于微极连续体有限元法考虑应变软化的岩土体稳定性分析

Abstract

Geotechnical stability analyses based on classical continuum may lead to remarkable underestimations on geotechnical safety. To attain better estimations on geotechnical stability, the micro-polar continuum is employed so that its internal characteristic length (4) can be utilized to model the shear band width. Based on two soil slope examples, the role of internal characteristic length in modeling the shear band width of geomaterial is investigated by the second-order cone programming optimized micro-polar continuum finite element method. It is recognized that the underestimation on factor of safety (FOS) calculated from the classical continuum tends to be more pronounced with the increase of 4. When the micro-polar continuum is applied, the shear band dominated by 4 is almost kept unaffected as long as the adopted meshes are fine enough, but it does not generally present a slip surface like in the cases from the classical continuum, indicating that the micro-polar continuum is capable of capturing the non-local geotechnical failure characteristic. Due to the coupling effects of 4 and strain softening, softening behavior of geomaterial tends to be postponed. Additionally, the bearing capacity of a geotechnical system may be significantly underestimated, if the effects of 4 are not modeled or considered in numerical analyses.

摘要

基于经典连续体理论的岩土体稳定性分析可能会显著低估岩土体的安全性。为了更好地评价岩 土体稳定性, 采用微极连续体, 以便其内部特征长度(lc)能够模拟剪切带宽度。以两个边坡为例, 基于 二阶锥规划的微极连续体有限元法, 研究内部特征长度在模拟岩土材料剪切带宽度中的作用。结果表 明, 随着lc 的增加, 对由经典连续体计算的FOS 的低估更加明显。当应用微极连续体时, 只要采用足 够细的网格, 剪切带受lc 主导基本保持不变, 所呈现的滑裂面与经典连续体不同, 表明微极连续体能 够捕捉非局部岩土破坏特征。由于lc 和应变软化的耦合作用, 岩土材料的软化行为有所滞后。此外, 如果在数值分析中不模拟或不考虑lc 的影响, 岩土体系的承载力可能会被严重低估。

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Author information

Affiliations

Authors

Contributions

CHEN Xi provided the concept and edited the manuscript. WANG Dong-yong performed some analyses and wrote the first draft. TANG Jian-bin performed some analyses and provided some numerical results. MA Wen-chen gave some revision suggestions on the first draft. LIU Yong edited the final revised draft.

Corresponding author

Correspondence to Xi Chen 陈曦.

Additional information

Conflict of interest

CHEN Xi, WANG Dong-yong, TANG Jian-bin, MA Wen-chen and LIU Yong declare that they have no conflict of interest

Foundation item

Projects(2017YFC0804602, 2017YFC0404802) supported by the National Key R&D Program of China; Project(2019JBM092) supported by the Fundamental Research Funds for the Central Universities, China

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Chen, X., Wang, Dy., Tang, Jb. et al. Geotechnical stability analysis considering strain softening using micro-polar continuum finite element method. J. Cent. South Univ. 28, 297–310 (2021). https://doi.org/10.1007/s11771-021-4603-3

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Key words

  • slope stability
  • strain localization
  • non-local geotechnical failure
  • micro-polar continuum
  • internal characteristic length

关键词

  • 边坡稳定性
  • 应变局部化
  • 非局部岩土破坏
  • 微极连续体
  • 内部特征长度