Evaluating coupled hydromechanical behavior of anisotropic rock mass using DEM
Journal
Bulletin of Engineering Geology and the Environment
Journal Volume
81
Journal Issue
3
Start Page
98
ISSN
14359529
Date Issued
2022
Author(s)
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. © 2022, Springer-Verlag GmbH Germany, part of Springer Nature.
Subjects
Anisotropy
Coupled hydraulic-mechanical model
Discrete element method (DEM)
Slate
Publisher
Springer Science and Business Media Deutschland GmbH
Type
journal article