| In recent years, since the distance between the left and right tunnel hole is large, or the holes are not in the same horizontal plane, the single-hole unidirectional tunnel is gradually emerging in the process of highway expansion. Disaster prevention and emergency rescue of the single-hole unidirectional tunnel is very difficult and there is no mature theory and engineering experience can learn from at home and abroad recently. So it is necessary to carry out the relevant technical studies to reduce the risk of tunnel safety so as to provide help for the similar tunnel engineering design.In this paper, based on "Guarantee of operational safety and rescue system for singlehole unidirectional Tunnel" project, we used Pyro Sim to establish a tunnel fire and evacuation numerical simulation model. Then we explored the development of temperature, CO concentration and visibility of Dakouzi tunnel under different conditions.The results showed that use the FDS+EVAC model to analysis single-hole unidirectional tunnel is quite feasible, it can simulate people’s evacuation and the motion of high temperature smog effectively; the size of fire and ventilation velocity have the greatest impact on temperature field, CO concentration field and smoke-field; critical wind speed not only can effectively suppress high-temperature smog spread to the upstream but also can ensure escape time for downstream people, for the fire of 20 MW and 50 MW in Dakouzi tunnel, critical wind speed were recommended 2.8m/s and 3m/s; regardless of the size of the fire and the ventilation velocity, considering the lateral distribution of high-temperature smog, people should evacuate along the midline of tunnel.Moreover, to achieve the purpose that help build a disaster prevention rescue system for similar tunnel, the paper also analyzed people’s evacuation law and evaluated casualties of Dakouzi tunnel under disaster conditions based on the research of variation of the tunnel fire. |
