A fractional-order two-surface plasticity model for over-consolidated clays and its application to deep gallery excavation

Wei Cheng, Ren Peng Chen, Zhen Yu Yin, Han Lin Wang, Fan Yan Meng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

8 Citations (Scopus)

Abstract

This paper proposes a novel fractional-order two-surface constitutive model for over-consolidated clays within the framework of the fractional plasticity and bounding surface theories. It incorporates the stress-fractional operator of the loading surface into isotropic and progressive hardening rules, thus obtaining an incremental stress–strain relation without an explicit plastic flow rule. The proposed fractional-order model can replicate the main features of over-consolidated clays well, including stiffness non-linearity, the occurrence of plastic strains before high peak strength, non-associativity, weak/strong dilatancy, and cyclic behavior. In model simulations on a set of element tests along different loading paths on natural Boom clay and remolded Fujinomori clay, the proposed model reveals better agreement than the modified Cam-Clay model (MCC). Next, the fractional-order model, ACC-2 model and MCC model are implemented via a user-defined material subroutine in ABAQUS with an explicit integration scheme based on the forward modified Euler method with automatic sub-stepping and error control. The different models are then applied to the fully coupled two-dimensional hydromechanical modeling of the excavation of two deep underground galleries in natural Boom clay. The results ultimately verify the validity and applicability of the proposed model.

Original languageEnglish
Article number105494
JournalComputers and Geotechnics
Volume159
DOIs
Publication statusPublished - Jul 2023

Keywords

  • Constitutive model
  • Excavation
  • Hydro-mechanical modeling
  • Over-consolidation ratio
  • Plasticity

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Computer Science Applications

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