An innovative tubular standing support incorporating PVC and FRP composites: laboratory tests

With the depletion of shallow resources, the drawbacks of conventional bolting system in sustaining the integrity of the roadway have drawn much attention. Developing the innovative secondary standing support is therefore to be urgent. This paper presents a hybrid tubular standing support, which consists of an exterior container made of PVC and fibre-reinforced polymer (FRP) composites and the infill material made of coal rejects and high flowable cementitious grout material. Compared with other marketable standing support, the combination application of the large rupture strain PVC tube and the FRP composite with high strength-to-weight ratio can provide the effective confinement to infill material, which may result in the strain hardening behaviour. The use of coal reject to generate the backfill material is believed to be effective and thus is attractive from the design aspect. To verify these mentioned advantages, a series of compression tests were conducted on this FRP-PVC tubular standing support (FPTSS) with different thickness of the FRP jacket. In addition, the compression tests were also conducted to investigate the compressive behaviour of FRP tubular standing support (FTSS) and PVC tubular standing support (PTSS). Test results indicated that the combination of FRP and PVC composite achieve the superior behaviour either in terms of the compressive strength or the deformation ability.