Experimental study of rock fracture behavior under direct tension using three-dimensional digital image correlation

Area of Science:

• Geotechnical Engineering
• Rock Mechanics
• Materials Science

Background:

• Assessing rock formation stability requires understanding mechanical properties under direct tension.
• Tage tuff's behavior under tensile stress is critical for geological engineering applications.

Purpose of the Study:

• To investigate the deformation behavior and crack extension of Tage tuff under direct tension.
• To analyze strain fields, crack propagation, localized deformation, and failure modes.

Main Methods:

• Utilized three-dimensional digital image correlation (3D-DIC) to analyze strain fields and crack propagation.
• Conducted direct tension tests on Tage tuff specimens.
• Scanned and analyzed surface failure patterns to determine failure modes and residual strength.

Main Results:

• Observed heterogeneous axial strain fields and localized deformation during the pre-peak stage.
• Identified crack extension directions indicating combined tensile and shear stresses.
• Found distinct stress-strain responses inside and outside localized bands, with significant changes in residual strength.

Conclusions:

• Direct tension tests on Tage tuff exhibit complex deformation and failure mechanisms.
• 3D-DIC is effective for analyzing localized deformation and crack propagation in rocks.
• The study enhances understanding of rock damage behavior under tensile stress, informing stability analyses.