The strengthening theory of steel fiber reinforced concrete and its application in tunnel engineering: A review

Steel fiber reinforced concrete (SFRC) is one of the fastest growing and most widely used fiber concrete as engineering structural material. Considering the importance of steel fiber concrete in tunneling applications, this paper reviews and discusses the damage mechanism of concrete and the crack arresting effect of steel fiber, and further investigates the application of SFRC in tunneling based on the reinforcement theory of SFRC. It was obvious that (1) steel fiber can not only delay the cracking damage of concrete, but also improve the deformation capacity of concrete, SFRC has excellent impact resistance and high tensile strength; (2) all the reinforcement theories can be considered to be developed on the basis of composite mechanics theory and fiber spacing theory by comprehensive improvement, but still need to further explore the reinforcement theory reflecting; (3) the combination of steel reinforcement and steel fiber will reduce the use of tunnel reinforcement, which is proven to be a better choice, because the content of steel fibers in SFRC has a certain degree of unevenness, so steel fibers can not completely replace the application of steel; and (4) SFRC applied to the node part of the tunnel structure is more effective, but the relevant research is less, in addition, steel fiber concrete tunnel node seismic resistance will be an important direction for future research. The relevant research in this paper can provide reference for the practical application of SFRC in tunnel engineering and other research directions.