Impact resistance characteristics of steel pipe shrinkable energy-absorbing bolt and its potential for rockburst mitigation and control

The rockburst disaster triggered by the nonlinear large-deformation characteristics of deep rock masses has been a worldwide problem in geotechnical engineering, severely constraining construction progress and safety in engineering projects. Therefore, it is imperative to intensify in-depth research on rockburst prevention measures. Based on the principle of steel pipe compressive deformation, a novel steel pipe shrinkable energy-absorbing bolt constant-resistance large-deformation bolt was proposed, which can provide a high constant resistance while accommodating a substantial amount of deformation. Building on previous research, the impact resistance of the steel pipe shrinkable energy-absorbing bolt constant-resistance large-deformation bolt was investigated through drop hammer impact tests. The test results indicate that: during the impact process, the working resistance of the steel pipe shrinkable energy-absorbing bolt constant-resistance large-deformation bolt remains stable within the range of 150 kN to 180 kN, demonstrating notable constant-resistance characteristics; the bolt absorbs a significant amount of energy with high efficiency, capable of absorbing up to 53 kJ of impact energy in a single instance; throughout the impact, the compression rate of the specimen only decreased by 0.54% to 1.43%, indicating relatively stable deformation. The steel pipe shrinkable energy-absorbing bolt constant-resistance large-deformation bolt exhibits excellent impact resistance, providing robust technical support for the prevention and control of rockburst disasters during underground engineering construction.