Abstract: To investigate the influence of steel fiber strength and shape on the flexural performance of steel fiber reinforced concrete (SFRC) and verify the feasibility of engineering application of large-diameter SRFC segments.This study relies on the Yellow River North Extension Project,which selects steel fibers with different strengths and aspect ratios to carry out four-point bending tests,uses DIC technology to observe crack evolution,and conducts field monitoring tests on negative ring segments.The results show that:(1) Compared with reinforced concrete (RC) beams,SFRC beams have better residual strength.The SFRC beam bending failure can be roughly divided into four stages:crack initiation stage,crack development stage,instability expansion stage,and failure stage;(2) The higher the tensile strength of steel fibers,the more beneficial it is for improving both tensile strength and flexural toughness.A higher aspect ratio of steel fibers results in higher residual flexural strength,but has a smaller impact on tensile strength;(3) Under the jacking load,the negative ring SFRC segment shows good performance,proving its feasibility in large-diameter shield tunnels.