Evaluating coupled hydromechanical behavior of anisotropic rock mass using DEM

Wen Jie Shiu, Meng Chia Weng*, Chia Chi Chiu, Po Lin Wu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Fluid transmission in geothermal reservoirs is significantly affected by foliated metamorphic rocks, which exhibit high anisotropy and heterogeneity. Coupled with hydromechanical analysis, we used discrete element-based software, which adopt the anisotropic properties of rock mass to investigate areas affected by hydraulic stimulation at geothermal sites. The proposed model was first validated using an existing benchmark problem concerning geothermal analysis under isotropic conditions. The analysis further considers the foliation-orientation-dependent shear behavior. The results indicate that the model with anisotropic angle α= 45 predicts the greatest increase in fracture aperture when accounting for the contributions of both shear dilation and joint normal stress drop. The analysis also examined the influence of anisotropy on the rock mass failure patterns. The zone of shear failure is highly affected by two factors: angle α and the stress state acting on the foliation plane. The case where α= 90 demonstrates an evident stress concentration area near the fracture end tips, thereby facilitating shear failure in the zone. The results demonstrate that the proposed model can reasonably simulate the anisotropic hydromechanical coupling behavior of metamorphic rock masses.

Original languageEnglish
Article number98
JournalBulletin of Engineering Geology and the Environment
Volume81
Issue number3
DOIs
StatePublished - Mar 2022

Keywords

  • Anisotropy
  • Coupled hydraulic-mechanical model
  • Discrete element method (DEM)
  • Slate

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