Abstract:The numerical calculation method was adopted to conduct an in-depth analysis of the control wind speed, smoke back-layering length and smoke temperature of dual-source fire in road tunnel sections and thus study the smoke control method of dual-source fire in road tunnel sections. The results show that under the dual-source fire scenarios, due to the dispersion of fire sources, the critical wind speed is mainly controlled by two fire sources. When the power of the two fire sources is the same or similar, there is a certain superposition effect between the two fire sources, with the critical wind speed subject to the joint influence of the two. When the power of the two fire sources is different, the critical wind speed mainly depends on the fire source with larger power, and the role of the fire source with smaller power is not obvious. The critical wind speed of dual-source (5 MW+5 MW) fire is 2.5 m/s, and the critical wind speed of dual-source (20 MW+20 MW) fire is 3.3 m/s, increasing to a certain extent compared with the same power of the single fire source. In contrast, the critical wind speed of dual-source (20 MW+5 MW) fire is 3.2 m/s, which is the same as that of the single-source 20 MW fire. The smoke temperature is affected by the power of the two fire sources, as is the critical wind speed. The smoke back-layering length is controlled by the fire size, and at the same ventilation speed, the smoke back-layering length increases with the growing fire size, which is not related to the power of the two fire sources.