Numerical simulation and comparative design of non-planar interlocking fibre reinforced concrete bricks for tunnel lining structure under impact loading

• An advanced FE model has been developed for interlocking SFRC tunnel structures. • The use of SFRC effectively enhances tunnel performance under impact. • Numerical simulation provides insights into interlocking SFRC structure behaviour. • The study provides essential design strategies for interlocking tunnel segments. In this study, the impact behaviour of tunnel lining structures constructed using a novel topological interlocking system with steel fibre reinforced concrete (SFRC) bricks is comprehensively investigated. A sophisticated finite element model is firstly developed to simulate the impact tests on the interlocking SFRC tunnel specimens. The model considers the geometric details of the main components of the test setup, including drop hammer, guide columns, interlocking tunnel specimen, rubber cover, and frames. Furthermore, a newly developed SFRC constitutive model is employed in the present model to accurately capture the dynamic behaviour of SFRC. By comparing the predicted results with experimental data, the developed numerical model has been demonstrated to be highly accurate. Six new non-planar topological interlocking bricks are then developed based on different patterns, and a parametric study is carried out to investigate the effect of geometric parameters on the dynamic response of the topological interlocking SFRC tunnel structures. Finally, recommendations for designing topological interlocking SFRC tunnel segments are provided based on the findings from this study.