Abstract: In current tunnel research and standards, fiber materials significantly improve the seismic performance of tunnels. Quantitative analyses are still insufficient in engineering design and research, especially the comparison of the difference in toughening effect of various fiber materials. To further clarify the toughness improvement effect of various fiber materials on tunnel structures, the authors summarize the toughening and crack resistance mechanism of various fiber materials based on existing case analysis, and analyze the seismic performance of fiber reinforced concrete segments and the application effect of seismic measures under special geologies. Finally, based on the axial constitutive models of various fiber-reinforced concrete, three-dimensional finite element structural analysis models of various fiber materials are constructed. Different vulnerability curves are fitted through seismic response analysis of various fiber material tunnels. Additionally, seismic toughness level of various fiber-reinforced concrete tunnels is evaluated based on classification index and judgment method of tunnels in different failure states. Under the same seismic action, it is found that the failure probability of ordinary concrete lining tunnel is higher than that of steel fiber reinforced concrete and mixed fiber reinforced concrete. In terms of improving the anti-failure performance of tunnels, the toughening and crack resistance of mixed fiber reinforced concrete is stronger than that of ordinary concrete. Therefore, the appropriate proportion of steel fiber content has a significant effect on improving the toughness of the plastic concrete matrix.

Key words: fiber concrete, tunnel, seismic performance; engineering practice, applicability, vulnerability, resilience