Angular grain fragmentation with DEM modeling: application to fault gouge shearing

Area of Science:

• Geophysics
• Computational mechanics
• Materials science

Background:

• Understanding fault gouge behavior is crucial for seismic hazard assessment.
• Traditional models often simplify grain shapes and fracture processes.

Purpose of the Study:

• To develop and validate a 2D Discrete Element Method (2D-DEM) framework for simulating grain fragmentation in fault gouge.
• To investigate the influence of grain properties on comminution and fault zone evolution.

Main Methods:

• Implemented a 2D-DEM model with angular, breakable grains.
• Incorporated realistic fracture mechanics and grain geometries.
• Conducted numerical Brazilian, oedometric, and shear tests; compared with laboratory data.

Main Results:

• Simulations reproduced strain localization, force chain evolution, and grain rounding via chipping.
• Model successfully captured the onset and progression of fragmentation.
• Fragmentation significantly impacts fault strength and mechanical stability.

Conclusions:

• The developed 2D-DEM framework is a robust tool for studying fault gouge fragmentation.
• The model enhances understanding of microstructural evolution and its effect on fault mechanics.
• Provides a foundation for future research on grain size and material property influences.