# Multi-Objective Real-Time Planning of Evacuation Routes for Underground Mine Fires
## 5 Case Studies
### Simulation Result and Discussion
Figure 8: Evacuation routes to different destinations. (**a**) Route to the main shaft. (**b**) Route to the auxiliary shaft. (**c**) Route to the incline shaft. (**d**) Route to the chamber refuge1. (**e**) Route to the chamber refuge2. If the evacuation command is issued immediately after the sensor alarm (12 s), a total of five feasible avoidance routes can be obtained at this point. In this case, a total of five paths were obtained. The escape targets of Paths 1, 2, and 3 are the main and second shafts and the east return air shaft, respectively, and they are surface exits, so they are prioritized over the routes with the refuge chamber as the target; because the fire occurred in the \(-110\) horizontal transport roadway under the west wind shaft, most of the paths with the west wind shaft as the escape target are in the smoke flow, and the algorithm cannot find a feasible solution that meets the rated protection time of the self-rescuer. Among all feasible solutions, Path 1 and Path 2 do not go through the smoke stream and have the highest security, but the equivalent length is relatively long. Path 3 has to walk in the smoke for about 681 s and it takes about 825 s to completely escape the smoke invasion area, so paths 1 and 2 should be given priority; when a path leading to a safe exit on the surface is available, the refuge chamber is generally not used as an escape target; on the contrary, when the disaster situation is out of control, that is, all surface exits cannot be solved and only the route with the refuge chamber as the target point has a feasible solution, the refuge chamber should be used as the escape target. Delays in evacuation can lead to a reduction in the number of possible routes and a deterioration in the safety of those routes. Evacuating immediately at the first sensor alarm, at 12 s, allows escape to all surface exits and refuge chambers. By evacuating at 300 s, all routes are affected by the smoke flow for a longer period of time and the route to the main shaft becomes impassable. At 1200 s, it is no longer safe to evacuate to the surface area and the only option is to go to the nearest refuge and wait for help. Since the resource vector in the label data structure of this algorithm is less than the equivalent length, the walking time in the smoke flow increases, which contains only two elements, and it is easy to form a dominant relationship between any two labels. Therefore, for any escape target, only one feasible path with the shortest length, the shortest walking time in the smoke flow, and meeting the rated protection time of the self-rescuer is obtained. We also compared planning algorithms with the classical disaster avoidance route and the results show that in scenarios with a small range of disaster impacts, the results of the present method are basically the same as those of the classical methods; in scenarios with severe disaster development and long distances between the avoidance starting point and the target point, the present algorithm has the potential to obtain multiple better solutions. Compared to traditional models, our approach integrates two critical safety indices: path length and path safety. In the event of a large-scale underground disaster, this method assesses the safety of available exits and plans feasible evacuation routes. Ultimately, it prioritizes these routes based on the safety indices, guiding underground personnel in making informed and rational decisions to evacuate.