A Time-Dependent Damage Constitutive Model for Brittle Rock Materials Based on Subcritical Damage Theory

Area of Science:

• Geotechnical Engineering
• Materials Science
• Rock Mechanics

Background:

• Understanding long-term rock deformation is vital for the safety and stability of civil engineering projects like dams and tunnels.
• Rock behavior under sustained loads directly influences structural integrity.
• Microcracks and stress corrosion significantly contribute to rock aging and failure.

Purpose of the Study:

• To investigate subcritical microcrack extension under stress corrosion using micromechanical methods.
• To develop a constitutive model for rock aging that accounts for cumulative damage over stress history.
• To provide a theoretical basis for assessing the long-term strength and stability of rock.

Main Methods:

• Micromechanical analysis of subcritical crack extension.
• Development of an aging constitutive model incorporating cumulative damage.
• Validation against experimental data from triaxial compression, creep, and relaxation tests.
• Frictional damage coupling analysis to derive long-term strength expressions.

Main Results:

• The proposed constitutive model accurately predicts rock deformation across various experimental conditions.
• Numerical results show strong consistency with extensive experimental data.
• Crack damage stress is identified as a key indicator for long-term rock strength.
• An analytical expression for the long-term strength of microcracked rock is derived.

Conclusions:

• The developed model effectively captures the aging damage patterns in rocks.
• The findings provide a robust theoretical framework for evaluating long-term rock performance.
• This research enhances the safety and reliability of large-scale rock engineering projects.