Experimental and numerical investigation on flexural and fracture performance of steel fiber reinforced shotcrete

This paper presents an experimental and numerical study on the flexural behaviour and fracture performance of steel fiber reinforced shotcrete (SFRS). Firstly, a series of full-scale tests were carried out under four-point bending test procedure to investigate the ultimate strength and failure behaviour of SFRS. Then, parameter calibration was conducted against several lab tests to obtain the accurate meso-scale parameters which could be employed in the 3D discrete element model of SFRS. Finally, a 3D discrete element model for the SFRS specimen was established based on the bond size theory in the parallel bonding model. The numerical results obtained from the proposed 3D discrete element model of SFRS showed a good agreement with the experimental results in terms of the flexural behaviour and the failure performance. By analyzing the bond failure micrograph and contact force chain distribution diagram between particles, the flexural resistance characteristics of SFRS beams were revealed, and the results showed that the random distribution of steel fibers can be well simulated by using the random function. The proposed 3D particle discrete element model and the meso-parameters of bonded granules obtained from the parameter calibration could provide good results to investigate the flexural behaviour and failure characteristics of SFRS.