Laboratory Experiments and Grain Based Discrete Element Numerical Simulations Investigating the Thermo-Mechanical...

Area of Science:

• Geotechnical Engineering
• Rock Mechanics
• Materials Science

Background:

• Thermo-mechanical loading affects engineering geological environments.
• Rock heterogeneity due to minerals and micro-defects influences mechanical and thermal properties.
• Elevated temperatures can decrease rock strength and stiffness, inducing micro-cracking.

Purpose of the Study:

• Investigate grain-scale thermal micro-cracking in sandstone.
• Quantify the impact of elevated temperatures on rock strength and stiffness.
• Validate numerical simulations against laboratory findings.

Main Methods:

• Performed laboratory triaxial experiments on sandstone at varying temperatures (20-100°C).
• Utilized discrete element method (DEM) simulations with Voronoi tessellation for grain-based modeling.
• Calibrated contact properties and applied mineral-specific thermal properties.

Main Results:

• Laboratory tests showed up to 15% peak strength reduction with increasing thermal loading.
• Micro-structural analysis revealed thermally induced micro-cracking.
• DEM simulations accurately replicated laboratory results, showing micro-crack formation and strength reduction.

Conclusions:

• Elevated temperatures induce micro-cracking in sandstone, significantly reducing its mechanical strength.
• Coupled thermo-mechanical modeling effectively simulates thermally induced damage and strength degradation.
• Findings are crucial for understanding rock behavior in geologically relevant thermal environments.