Comparison of Glass-fibre Reinforced Polymer Rock Bolts with Double Corrosion Protection Steel Rock Bolts for Use in Tunnel Applications

摘要

Double corrosion protection (DCP) rock bolts have evolved to become complicated assemblies comprising numerous components. This complexity is mainly associated with durability considerations including potential exposure to adverse groundwater conditions and ensuring separation of dissimilar metals within the bolt assembly itself. Recent progress in the construction of glass-fibre reinforced polymer (GRP) rock bolts have the potential to provide a viable alternative to conventional steel rock bolts in civil tunnelling applications. The durability of the material results in a much simpler bolt detail and permits the use of resin rather than solely cement based grouts. This paper presents the findings of the comparative structural testing of GRP bolts with conventional DCP steel bolts. The axial load performance, including stiffness, ultimate capacity and ductility of bolts are compared. Shear behaviour of bolts is considered, including durability issues associated with damage to the plastic sleeve used in DCP bolts. The paper also considers other issues which are relevant to the design of temporary and permanent rock bolts used in tunnel support, such as initial tensioning and grouting. Long-term performance, including durability and creep are also reviewed.