Abstract
This study used experimental and numerical simulation methods to discuss the attenuation mechanism of a blast inside a tunnel for different forms of a tunnel pressure reduction module under the condition of a tunnel near-field explosion. In terms of the experiment, a small-scale model was used for the explosion experiments of a tunnel pressure reduction module (expansion chamber, one-pressure relief orifice plate, double-pressure relief orifice plate). In the numerical simulation, the pressure transfer effect was evaluated using the ALE fluid–solid coupling and mapping technique. The findings showed that the pressure attenuation model changed the tunnel section to diffuse, reduce, or detour the pressure transfer, indicating the blast attenuation effect. In terms of the effect of blast attenuation, the double-pressure relief orifice plate was better than the one-pressure relief orifice plate, and the single-pressure relief orifice plate was better than the expansion chamber. The expansion chamber attenuated the blast by 30%, the one-pressure relief orifice plate attenuated the blast by 51%, and the double-pressure relief orifice plate attenuated the blast by 82%. The blast attenuation trend of the numerical simulation result generally matched that of the experimental result. The results of this study can provide a reference for future protective designs and reinforce the U.S. Force regulations.
Highlights
Tunnels are usually concealed and sheltered by landforms and ground objects to prevent a direct hit from enemy weapons, meaning the transfer of a blast is obstructed and attenuated by orifice plate attenuators, expansion chambers, explosion doors, and tunnel branches.Studying the dynamic response of structures subjected to air blast loading has received a lot of attention in the last few decades [1,2,3,4,5,6,7,8,9,10]
The result showed that the blast inside the tunnel attenuated as the distance increased, and the detonation wave impulse inside the tunnel could be regarded as a constant
The near-ground and variable tunnel explosion experiments were performed, the numerical simulations and U.S Force empirical equations were used for analysis and validation, and related empirical equations were established, which are intended to establish a tunnel blast protection evaluation and improvement mechanism to provide a reference for subsequent tunnel building and renovation
Summary
Tunnels are usually concealed and sheltered by landforms and ground objects to prevent a direct hit from enemy weapons, meaning the transfer of a blast is obstructed and attenuated by orifice plate attenuators, expansion chambers, explosion doors, and tunnel branches. In terms of studies regarding tunnel explosion protection, in 1992, Song et al [11] used a reduced specimen of a steel ammunition storage magazine, with the internal dimensions of 100 × 50 × 23 cm and loading density of 16.7 kg/m3 ; detonated 1.9 kg of C-4 explosives inside the specimen; and discussed the influence of Straight, Elbow, and Dead-End channels on the blast transfer. In the EMI equation (TM 5-855-1, 1998) [14], the proposed empirical equation can be used to estimate the blast inside a tunnel from an explosion outside the tunnel. In 2007, Ishikawa and Beppu [17] compiled the protective structure explosion experiment results of Johoji et al from 1965 to 1981 They analyzed the blast transfer attenuation in vertical bar, branch, and mesh tunnels. The near-ground and variable tunnel explosion experiments were performed, the numerical simulations and U.S Force empirical equations were used for analysis and validation, and related empirical equations were established, which are intended to establish a tunnel blast protection evaluation and improvement mechanism to provide a reference for subsequent tunnel building and renovation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
