Abstract: A novel tunnel lining and segment i.e. the multi-cell steel tube-sandwich concrete-fibre reinforced polymer (FRP) tube-core concrete (MCSCFC) segment was proposed. The MCSCFC segment comprised the following four parts: multi-cell square steel tube; concrete between FRP tubes and square steel tube walls; FRP tubes placed in cells; core concrete confined by FRP tubes. To understand mechanical behaviors of the MCSCFC and conventional reinforced concrete (RC) segments under the lateral uniform compression, the 4 segment model specimens (3 MCSCFC and 1 RC) with different thicknesses of FRP tubes were tested under the lateral uniform compression. The failure modes, load-displacement and load-strain curves of segment model specimens were analysed and discussed. Experimental investigation-based conclusions were drawn: ①The MCSCFC segments exhibit distinctive post-yield hardening behaviour under the lateral uniform compression; ②compared to that of the RC segment, the bearing capacity of MCSCFC segment increased up to 41.8% when the segment thickness was reduced by 39.4%.

Key words: segment, confined concrete, FRP tube, post-yield hardening