Performance of metal circular tube under different loading amplitudes and dynamic resistance-yielding mechanism

Abstract

As coal mining depth increases, the characteristics of “high ground stress, high ground temperature, high osmotic pressure, and mining disturbance” become increasingly pronounced, posing new challenges to the stability of the surrounding rock roadway. Amplitude is a key parameter affecting disturbance strength. A cyclic loading and unloading experiment was conducted under different amplitudes to explore the effect of metal circular tubes, used as energy-absorbing components, on the protection performance of anchor bolt tails. This experiment further revealed the competitive protection mechanism of the metal circular tube, termed “resistance - yielding”. The research results indicate that the metal tube incurs damage and accumulates it with the increase of loading amplitude in the pre-peak stage, leading to a decrease in its peak load. The metal tube absorbs external energy robustly through its elastic-plastic deformation. In the platform stage, a high amplitude load causes the peak load displacement to increase and its stable energy-absorbing stroke to decrease. Plastic energy dominates the main position of energy absorption, and the metal circular tube forms a dynamic competitive relationship of “resistance-yielding” with external stresses. Throughout the entire energy absorption process, the total energy absorption decreases with the increase of amplitude. The research results investigate the effect of amplitude on the performance of metal circular tubes and demonstrate the feasibility of applying metal circular tubes as energy-absorbing members at the end of anchor rods, which can provide theoretical guidance for the prevention of disaster accidents in mines caused by disturbances.