Research on Fire Smoke Controlling Effect of Submarine Road Tunnel Based on FDS

Taking submarine road tunnel as the research objective, numerical calculation model of fire smoke controlling in rectangular underwater tunnel was established by FDS. The adaptability of lateral concentrated exhaust mode in tunnels of variable widths is obtained according to analysis of smoke distribution and smoke exhausting efficiency under different working conditions. The results are as follows: The increase of width results in the decrease of smoke exhausting efficiency. In the four-lane dual-directional tunnel, the smoke exhausting efficiency is 83.4%; while that of twelve-lane dual-directional tunnel is only 55.2%. The wind velocity is higher in the area near the lateral exhaust valves; and which is lower in the area far from the exhaust valves. The influence of wind velocity for lateral exhaust valves is limited. With the increase of width, the wind velocity of cross-section decreases dramatically. In a four-lane dual-directional tunnel, the wind velocity of the right wall decreases by 32%, and that in twelve-lane dual-directional tunnel decreases by 59.6%. For large-span rectangular tunnels of eight-lane dual-directional or even wider ones, the lateral centralized exhaust mode shows poor fire smoke controlling effect.