Damage Evolution Constitutive Behavior of Rock in Thermo-Mechanical Coupling Processes

Area of Science:

• Geotechnical Engineering
• Materials Science
• Continuum Mechanics

Background:

• Rock mechanics is critical for engineering structures subjected to thermal and mechanical loads.
• Existing models often do not fully capture the entire process of rock failure under coupled thermomechanical conditions.
• Understanding thermal damage is essential for predicting the performance and safety of rock masses.

Purpose of the Study:

• To develop a unified thermomechanical (TM) constitutive model for predicting rock behavior under coupled thermal and loading conditions.
• To incorporate key factors like the Drucker-Prager yield criteria, compaction, and thermal damage into a single model.
• To accurately simulate the entire process of rock deformation and failure, including compaction and post-failure stages.

Main Methods:

• Introduction of a triple-shear Drucker-Prager yield criteria into a new TM constitutive model.
• Inclusion of compaction coefficient (K), damage variable correction factor (δ), and thermal damage variable (D).
• Modeling of rock compaction and strain softening under uniaxial compression and thermal attack, validated against experimental data.

Main Results:

• The developed TM unified constitutive model accurately predicts the uniaxial compressive strength of granite under coupled thermomechanical effects.
• The model shows good agreement with experimental stress-strain curves throughout the entire process, including compaction and post-failure stages.
• The study quantifies the nonlinear nature and significant weakening effect of the thermomechanical coupling on rock specimens.

Conclusions:

• The new TM unified constitutive model provides a robust framework for analyzing rock damage evolution under high temperatures and loading.
• The model effectively represents the stress-strain behavior of rocks, particularly in the post-failure stage.
• This research offers valuable insights for future studies on rock damage propagation and mechanical responses in thermomechanical environments.