Abstract: In order to study the basic characteristics of smoke movement in the interlayer of the underground depot with superstructure, a 1:50 scale model test bench was built, and the results were compared with the FDS full-scale simulation. Under the determined source power, five different wind speeds were set in the hybrid ventilation system, and a natural ventilation system was used for comparative experiments. The results showed that the mixed ventilation system can control the flue gas better than the natural ventilation system; a stable smoke layer can be formed at a wind speed of 1.4 m/s; in natural ventilation and hybrid ventilation systems, the concentration of carbon monoxide in the interlayer is always less than 0.06%, but in natural ventilation systems, carbon monoxide will accumulate at the ceiling of the interlayer, which is not conducive to evacuate.

Key words: underground depot, FDS, scale experiment, CO concentration, smoke control