Prediction of large-scale failures of rock from small-scale characteristics of the soil medium using multiscale modelling.

TY - CONF

T1 - Prediction of large-scale failures of rock from small-scale characteristics of the soil medium using multiscale modelling.

AU - Mourlas, Christos

AU - Pardoen, Benoît

PY - 2021/5/27

Y1 - 2021/5/27

N2 - The geomaterials such as soils and rocks are multiphase porous media with complex structure that is characterised by heterogeneity and possible anisotropy at various scales. It is obvious that, the heterogeneous nature of the material is originated by the small-scale properties1 . The microscopic behaviour of rocks is characterised by the material and morphological (grain shape and size) properties of its components and their interactions. The accurate reproduction and influence of these microscale characteristics on the material behaviour and damage at large scale remain a complex issue. This question becomes crucial when investigating the underground stability during excavation works such as galleries and tunnels 2 3 . In this study, the microstructure characteristics are embedded in a representative volume element (RVE) 4 . A double-scale numerical framework, with finite element resolution at both scales (FEM²) and computational homogenisation, is considered5 6 . The influence of the microstructural characteristics of heterogeneous rocks and the effect of different inter-granular properties on their macroscopic behaviour, are examined. Additionally, a predictive strategy which is based on the connection between the failure modes of the RVE and the failure mechanisms of the macroscale structure is also presented. This study investigates the effect of the microcracking on the regularised shear banding in a soil specimen during biaxial shear test and the development of the Excavation Damaged Zone (EDZ) around tunnels. The objective of this work, is to explain the failure mechanisms observed up to the engineering scale of underground structures through the morphological and material small-scale characteristics of the RVE.

AB - The geomaterials such as soils and rocks are multiphase porous media with complex structure that is characterised by heterogeneity and possible anisotropy at various scales. It is obvious that, the heterogeneous nature of the material is originated by the small-scale properties1 . The microscopic behaviour of rocks is characterised by the material and morphological (grain shape and size) properties of its components and their interactions. The accurate reproduction and influence of these microscale characteristics on the material behaviour and damage at large scale remain a complex issue. This question becomes crucial when investigating the underground stability during excavation works such as galleries and tunnels 2 3 . In this study, the microstructure characteristics are embedded in a representative volume element (RVE) 4 . A double-scale numerical framework, with finite element resolution at both scales (FEM²) and computational homogenisation, is considered5 6 . The influence of the microstructural characteristics of heterogeneous rocks and the effect of different inter-granular properties on their macroscopic behaviour, are examined. Additionally, a predictive strategy which is based on the connection between the failure modes of the RVE and the failure mechanisms of the macroscale structure is also presented. This study investigates the effect of the microcracking on the regularised shear banding in a soil specimen during biaxial shear test and the development of the Excavation Damaged Zone (EDZ) around tunnels. The objective of this work, is to explain the failure mechanisms observed up to the engineering scale of underground structures through the morphological and material small-scale characteristics of the RVE.

UR - https://www.cfmr-roches.org/manifestations-et-evenements/passees

M3 - Abstract

SP - 3

EP - 3

T2 - Séance technique

Y2 - 27 May 2021 through 27 May 2021

ER -