NUMERICAL STUDY ON NPR CABLE-ROCK INTERACTION USING3D DISCRETE-CONTINUOUS COUPLING METHOD

Due to the characteristics of efficient energy absorption, constant-resistance-large-deformation (NPR) cables have been applied in many rock slopes and mining engineering for monitoring and reinforcement. The NPR cable-rock interaction differs from that of traditional cables owing to the pipe-shaped expansion during the working process, and it affects the performance of a NPR cable reinforcement system. Therefore, a coupled numerical method is used to study the characteristics of the NPR cable-rock interaction under static pull-out loading. The structure of the NPR cable is considered as a continuous zone via the finite-difference method (FDM), and the surrounding rock and grouting material was modelled by the discrete element spherical particles via the discrete-element method (DEM). The micro parameters of the grouting material and surrounding rock were carefully calibrated, and the comparisons of corresponding experimental tests in the laboratory to verified the macro parameters of the NPR cable. The numerical results were carefully discussed and analyzed. The constant-resistance forces between a onefold NPR cable and the NPR cable reinforcement system were compared. The spatial arrangement of the normal and shearing stresses on the cable-rock interface was obtained. Furthermore, the failure mode of grouting material and surrounding rock was researched at the micro scale. The results describe the interaction between the NPR cable and the surrounding rock and reveal its special anchorage mechanism, and help improve and predict the performance of the NPR cable reinforcement system.