Comparative analysis of mechanical properties and support effects of polyester bolt and traditional steel bolt

Polyester bolt, which is lighter, stronger and shows better resistance to corrosion than the traditional steel bolt, has gradually been used in excavation and support of slope, tunnels and underground caverns. The finite difference software FLAC^3D is used to simulate the pull-out tests on the traditional steel bolt and polyester bolt. The mechanical responses of the bolts during the pull-out process are analyzed. The support effects of the two bolts in strain-softening surrounding rock are studied, and the calculated results are compared based on the deformation of surrounding rock, area of plastic zone, stress in preliminary support structure and yield state of bolts. The results show that as the anchorage length approaches a certain value, compared with the traditional steel bolt, the polyester bolt can sustain larger pull force; while the tunnel is further excavated, the polyester bolt has an advantage over the traditional steel bolt in controlling the rock deformation, and the plastic zone and reducing the pressure on the preliminary support.