Anchoring effect of NPR cables under dynamic conditions and its engineering applications

Anchor cable failures due to dynamic loads are common in rock engineering. Traditional cables could be invalid to accommodate large displacement and deformation in geomaterials. Cable body failure often occurs due to limitations in mechanical characteristics and small deformation of traditional anchor cables. The new Negative Poisson's ratio (NPR) cable has the mechanical properties of high strength, toughness, and impact resistance due to its special structure. This study investigated the response of NPR cable anchorage systems under dynamic loading through laboratory tests and numerical modeling. The dynamic pull-out tests on NPR cable under drop hammer loading were conducted to examine the behavior of dynamic perturbation mitigation. To investigate the intricate NPR cable-rock interaction, a coupled model utilizing the distinct element method (DEM) and the finite difference method (FDM) was established. The NPR cable was encircled by grouted concrete and sandstone modeled with discretized particles using the distinct element method. The numerical results and the NPR cable-rock interaction under dynamic loading were carefully analyzed and discussed. The NPR cable-rock interaction, including the relative sliding displacement between the cone and the pipe, the accumulated relative sliding displacement between the cone and the pipe, the radial displacement of the pipe, and the contact forces of concrete and rock, were carefully studied through numerical simulation. Furthermore, a microscopic analysis was conducted to investigate the failure modes exhibited by the grouting material and the surrounding rock. Finally, NPR cables are utilized to reinforce the slope stability in open-pit mines. Their applications demonstrate that NPR cables can mitigate slope failures and play a crucial role in anticipating and providing timely warnings of slope instability, alongside a comprehensive slope stability monitoring system. This study offers valuable insights that can contribute to predicting and enhancing the performance of NPR cables in mitigating the effects of dynamic disasters.