I obtained the following conclusions based on the above analysis:
(1) When the distances of the exhaust ports were 40m or 50m and we opened the two exhaust ports, it can not be timely discharge of fire smoke.
(2) When the distances of the exhaust ports were 40m, its economic investment was the larger and its security was the higher compared with the original scheme exhaust port distance 60m.
(3) When the distances of the exhaust ports were 50m, its economic investment was the appropriate and its security was more moderate compared with the original scheme exhaust port distance 60m.
Therefore, this paper recommended the scheme which would open three exhaust ports and the distances of them was 50m as the most reasonable optimum proposal.
Key words: Tunnel fire; Numerical simulation; The number of exhaust ports; The distance of exhaust ports