New Research Reveals Insights into Geomechanics and Geophysics

Researchers from China University of Mining and Technology have conducted a comprehensive study to investigate the synergistic mechanism of confining pressure and anchorage length on anchorage body bearing capacity. The study employed laboratory pull-out tests, acoustic emission monitoring, and ABAQUS numerical simulation to examine the mechanical response and failure evolution under varying confining pressures and anchorage lengths. The research, funded by Zhiqiang Zhao, aims to provide a deeper understanding of the behavior of anchorage bodies under different confining pressure gradients and anchorage lengths.

Key Takeaways:

• The study found that the bolt pull-out process comprises four stages: elastic deformation, plastic yield, post-peak softening, and friction slip.
• Increasing confining pressure from 0 to 15 MPa raised the ultimate bearing capacity of long anchorage specimens by 62%, 37%, and 15%, and short specimens by 61%, 37%, and 27%, respectively.
• Higher confining pressure enhances bearing capacity, but the increase rate diminishes with pressure.
• Under long anchorage conditions, increased confining pressure significantly influences the anchorage body failure mode.
• The study used a high-precision confining pressure loading system and acoustic emission monitor to acquire pull-out load-displacement curves, acoustic emission energy, and ring count parameters.
• A numerical simulation framework incorporating a nonlinear bond-slip model was used to verify test reliability and predict the behavior of anchorage bodies.

Statistics:

• The study found that increasing confining pressure from 0 to 15 MPa raised the ultimate bearing capacity of long anchorage specimens by 62% (0.62), 37% (0.37), and 15% (0.15), and short specimens by 61% (0.61), 37% (0.37), and 27% (0.27), respectively.
• The bolt pull-out process was found to comprise four stages, with increasing confining pressure affecting the failure mode under long anchorage conditions.

Sources:

• Mechanical response characteristics and failure evolution law of anchorage body under different confining pressure gradient and anchorage length. Geomechanics and Geophysics for Geo-Energy and Geo-Resources, 2025, 11(1): 1-20.
• Physics Week. October 21, 2025. "Findings from China University of Mining and Technology in Geomechanics and Geophysics Reported (Mechanical response characteristics and failure evolution law of anchorage body under different confining pressure gradient and anchorage length)" p. 72.