Enhancing disaster prevention and structural resilience of tunnels: A study on liquid hydrogen leakage, diffusion, and explosion mitigation

• This study reports the first explosion assessment following LH2 leakage in a tunnel. • The explosion of LH2 leakage is more severe than that of hydrogen gaseous tank leakage. • Simulation results have been verified by theoretical calculations and analogous data. • The potential maximum-danger positions are identified. • Suction ventilation and high humidity reduce explosion overpressures and ignition risks. The increasing adoption of liquid hydrogen (LH2) as a clean energy carrier presents significant safety challenges, particularly in confined underground spaces like tunnels. LH2′s unique properties, including high energy density and cryogenic temperatures, amplify the risks of leaks and explosions, which can lead to catastrophic overpressures and extreme temperatures. This study addresses these challenges by investigating the diffusion and explosion behaviour of LH2 leaks in tunnels, providing critical insights into disaster prevention and structural resilience for underground infrastructure. Using advanced numerical simulations validated through theoretical calculations and experimental analogies, the study analyses hydrogen diffusion patterns, overpressure dynamics, and thermal impacts following an LH2 tank rupture. Results show that LH2 explosions generate overpressures exceeding 50 bar and temperatures surpassing 2500 °C , far exceeding the hazards posed by gaseous hydrogen leaks. Mitigation measures, such as suction ventilation and high humidity, significantly reduce explosion impacts, underscoring their value for tunnel safety. This research advances understanding of hydrogen safety in confined spaces, demonstrating the importance of integrating mitigation measures into tunnel design. The findings contribute to disaster prevention strategies, offer insights into optimizing safety protocols, and support the development of resilient infrastructure capable of accommodating hydrogen technologies in a rapidly evolving energy landscape.