Mechanical behavior analysis of fully grouted bolt under axial load

Area of Science:

• Geotechnical Engineering
• Mechanical Engineering
• Materials Science

Background:

• Fully grouted bolts are crucial in underground structures.
• Understanding their mechanical behavior under axial load is essential for safety and efficiency.
• Existing models may not fully capture the complex bond interface behavior.

Purpose of the Study:

• To propose a simplified spring-element analysis method for fully grouted bolts.
• To develop and analyze various load transfer models for bolt-grout interaction.
• To provide a comprehensive understanding of the mechanical behavior of fully grouted bolts.

Main Methods:

• Discretization and force balance analysis of mass spring elements.
• Development of three coupling models for the bolt-grout bond interface: slider, spring, and spring-slider.
• Deduction of five load transfer models using the spring-element method.
• Experimental verification using pull-out tests on smooth and threaded steel bolts.

Main Results:

• Derived bolt displacement, axial force, and shear stress distribution functions for each model.
• Validated the proposed models through experimental pull-out tests.
• Demonstrated the effectiveness of the spring-element analysis method in predicting bolt behavior.

Conclusions:

• The proposed spring-element analysis method provides a simple and understandable approach to studying fully grouted bolt mechanics.
• The study enhances the comprehensive understanding of fully grouted bolt behavior under axial loading.
• Experimental results validate the proposed models and the overall analysis method.