Blast responses of shallow-buried prefabricated modular concrete tunnels reinforced by BFRP-steel bars

This paper reports the anti-blast performance of shallow-buried prefabricated modular tunnel reinforced by basalt fiber-reinforced polymer (BFRP) -steel bars. Three concrete arch members with steel bars and three concrete arch members with BFRP-steel bars were fabricated, with the other arch parameters kept constant. The three identical arches were assembled into an integral structure and then buried in soil for field anti-blast experiments. Through the experiment, the pressure on the vault, the displacement and acceleration of the vault, the strain in the reinforcement bars and the macroscopic damage of the arches under the blast load were determined. To evaluate the damage of the arch tunnel, a residual load-bearing capacity test was conducted on the arch members after the explosion experiment. The experimental results showed that the BFRP-steel bars reinforced concrete arch exhibited a higher load-bearing capacity and more safety redundancy than the steel bars reinforced concrete arch, and that the BFRP-steel bars could inhibit the occurrence of concrete cracks to a certain extent. A comparison between the arches assembled at different positions showed that the prefabricated modular tunnel can be simplified directly as a two-dimensional arch structure under the blast load for analysis and calculation.