Study on the Standard of Fire Disaster Prevention for Super Large Cross Section Immersed Tunnels

Relying on the Shenzhen-Zhongshan subsea immersed tunnel project, combined the characteristics of highway tunnel traffic, the method of fire standard for super large cross section submarine immersed tunnel is proposed. Through the analysis of road tunnel fire cases, it is clear that vehicle spontaneous combustion is the main cause of tunnel fires. The ignition distance of different fire scales under the condition of tunnel traffic jam is determined by theoretical calculation. Through numerical simulation, when a super large cross section submarine immersed tunnel is fired under the condition of traffic jam, the scale of the fire is enlarged due to the ignition of the vehicle, and the fire scale design value of the super-large cross section submarine immersed tunnel is obtained. Based on the most dangerous situation of vehicle spontaneous combustion in an uni-direction four-lane tunnel, according to the actual traffic composition, the probabilistic method is used to analyze the composition of the laterally ignited vehicle and the probability of the event. It shows that the maximum probability of being ignited in a four-lane tunnel is one coach and one truck, and the fire prevention standard for Shenzhen-Zhongshan immersed tunnel is determined to be 50MW.