Performance evaluation of novel energy-absorbing anchor cables with expansion–friction structures for supporting roadways prone to rock bursts

The powerful impact generated by a rock burst in a coal mine roadway can easily cause ordinary steel strand anchor cables to break, detach, and deform. To address these issues, an expansion–friction energy-absorbing structure designed for installation on ordinary steel strand anchor cables was developed, establishing a novel type of energy-absorbing anchor cable. To investigate the macroscopic deformation characteristics and mechanical properties of the expansion–friction structure and evaluate its performance, static tests were conducted on a 5000 kN servo press. The research results indicate that this energy-absorbing structure possesses dual energy absorption characteristics, namely, plastic expansion deformation and frictional sliding energy dissipation. The deformation characteristics manifest as symmetrical plastic deformation and stable friction deformation and exhibit strong controllability, repeatability, and energy absorption stability. In general, as the cone angle and expansion increase, the deformation of the energy-absorbing structure becomes more pronounced. From the perspective of constant resistance, as the cone angle and expansion increase, the constant resistance gradually increases. The stability of the constant resistance is best at cone angles of 10° and 15° and expansion amounts of 0.5 and 1.5 mm, respectively. Based on the principle of energy absorption, an evaluation index for the mechanical performance of the energy-absorbing structure is proposed. The analysis revealed that the constant resistance, unit displacement energy absorption, and total energy absorption ranges of the expansion–friction energy-absorbing structure are 139.60 to 652.88 kN, 0.41 to 0.61 kJ/mm, and 34.25 to 149.25 kJ, respectively. Therefore, it exhibits good static load control and dynamic load energy absorption mechanical performance. This structure can reduce the probability of impact failure that arises with ordinary anchor cables, thereby improving the stability control effect of energy-absorbing and anti-impact anchor cables on the rock surrounding the roadway and achieving effective control of roadway rock bursts.