Experimental and numerical investigation of shock wave propagation and thermal effects induced by thermobaric explosive detonation in corrugated steel-lined tunnels

Abstract

The accelerating expansion of underground space utilization has exposed tunnel engineering to escalating hazards from the synergistic effects of shock wave and fireball thermal radiation caused by explosive incidents. The traditional monolithic lining system has been demonstrated to exhibit markedly insufficient energy dissipation capability and disaster mitigation effectiveness. This study establishes a finite volume model (FVM) incorporating afterburning effects to investigate shockwave propagation and fireball thermal effects in corrugated steel-lined tunnels. It is demonstrated that corrugated grooves disrupt shockwave reflection continuity, inducing intermittent reflections and wavefront fragmentation, accelerating energy dissipation and reducing peak overpressure by 27.3 % in tunnels with λ = 150 mm and h = 60 mm versus concrete linings. The attenuation efficiency of shock wave impulse in corrugated steel-lined tunnels decreases monotonically with increasing λ/h ratio. The lower the λ/h ratio, the larger the effective scattering area, causing wavefront fragmentation and multi-path interference, which in turn enhances energy dissipation through wavefront disruption. Additionally, the corrugated structure generates turbulent disturbances and periodic vortex damping effects. These effects causing the expansion of localized high-temperature zones, simultaneously lead to a substantial reduction in fireball volume due to intensified convective heat dissipation and path disruption. In the corrugated steel-lined tunnel with a corrugation wavelength of λ = 150 mm and wave height of h = 70 mm, the maximum propagation distances of fireballs are decreased by 13.1 %. By establishing shockwave prediction models with wall roughness correction, the parameter-dependent energy dissipation mechanisms are quantified, thus providing theoretical foundations and technical support for optimizing tunnel lining design and enhancing underground space protection capabilities.