Strain-softening model for granite and sandstone based on experimental and discrete element methods

Area of Science:

• Geotechnical Engineering
• Rock Mechanics
• Computational Geology

Background:

• Understanding rock mass behavior under stress is crucial for infrastructure design.
• Strain-softening is a critical failure mechanism in rocks like granite and sandstone.
• Macroscopic and mesoscopic approaches offer complementary insights into rock deformation.

Purpose of the Study:

• To analyze the strain-softening behaviors of granite and sandstone.
• To develop a strain-softening model for hard and soft rocks.
• To investigate rock failure mechanisms at both macroscopic and mesoscopic levels.

Main Methods:

• Laboratory triaxial compression tests to obtain stress-strain curves.
• Discrete Element Method (DEM) with PFC software for numerical simulation.
• Calibration of DEM parameters using experimental data.

Main Results:

• Characterized strain-softening in granite and sandstone under varying confining pressures.
• Verified the feasibility of DEM by comparing simulation with experimental results.
• Analyzed mesoscopic crack propagation and particle displacement fields during failure.

Conclusions:

• Combined methods provide a comprehensive understanding of hard and soft rock strain-softening.
• Failure patterns differ: sandstone is affected by confining and axial stress, while granite is primarily affected by axial stress.
• Research provides a foundation for analyzing rock strain-softening behavior.