Blast resistance performance of BFRP bar‐reinforced concrete box utility tunnel: A theoretical and experimental study

Abstract This study examined the blast resistance of shallow‐buried concrete box utility tunnels reinforced with basalt fiber‐reinforced polymer (BFRP) bars through blast tests and theoretical analysis. Five specimens were tested under two TNT charge levels to investigate elastic response, damage evolution, and failure modes. The dynamic responses of the roof slab, side walls, and bottom slab were measured and compared. Based on the test observations, a simplified theoretical model is proposed in which the roof slab is idealized as an orthotropic plate and the surrounding soil is represented by a two‐parameter dynamic foundation incorporating Winkler normal stiffness, Pasternak shear interaction, and radiation damping. Based on this two‐parameter foundation‐orthotropic plate model and a multimodal solution procedure, the blast‐induced displacement histories can be predicted with reasonable agreement with the test results. These findings provide both experimental support and a practical analytical tool for evaluating the blast response of shallow‐buried BFRP‐reinforced utility tunnels.