Congestion-Based Earthquake Emergency Evacuation Simulation Model for Underground Structure
Abstract
:1. Introduction
2. Evacuation Simulation Model Using Dijkstra Algorithm
2.1. Evacuation Model Using the Dijkstra Algorithm
2.2. Input Parameters for the Underground Station Evacuation Model
2.2.1. Geometry of the Underground Structure
2.2.2. Number of Evacuees and Evacuation Time
2.3. Seismic Risk Analysis for the Underground Station
2.4. Determination of the Evacuation Speed
2.4.1. Speed Reduction Due to Seismic Risk
2.4.2. Evacuation Speed Reduction Due to Evacuee Congestion
3. Evacuation Simulation Results and Discussion
4. Conclusions
- A model to derive the optimal evacuation route in the event of an earthquake was developed considering evacuee congestion using a simplified representation of a Korean subway station cross-section with three basement floors. Results of previous studies, wherein the risk according to the ground type and depth was assessed, were used in the seismic risk analysis, and the evacuation speed reduction due to the seismic damage to the structure was evaluated. The evacuation speed reduction due to evacuee congestion was defined using the evacuation capacity of the subway station. The evacuation speed was reduced to 1/3 of the original speed when the number of people exceeded the evacuation capacity. The effects of seismic damage and crowding beyond the evacuation capacity on evacuation time were analyzed using the Dijkstra algorithm;
- When the evacuation speed reduction due to congestion was not considered, the evacuation route was focused on the left exit (which was relatively less damaged) than the right exit (which was subject to severe seismic damage). This demonstrated the reduction in the evacuation speed due to seismic damage; the resulting concentration of evacuees in certain sections could increase congestion;
- When the evacuation route was derived considering the reduction in the evacuation speed due to congestion, the Dijkstra algorithm searched for alternative routes to account for the evacuation speed reduction. In particular, in some sections, the optimal evacuation route, which was the relatively less damaged left passage when evacuee congestion was not considered, changed to the right passage when an alternative route was derived considering congestion. This change may be attributed to the reduction in the evacuation speed due to the concentration of evacuees in the relatively less damaged left passage and the consequent derivation of an alternative route by the algorithm;
- When the original route was chosen for evacuation, despite the reduction in evacuation speed due to congestion, the evacuation time increased significantly due to increased congestion and reduced evacuation speed. When an alternative route derived by considering congestion was used, the evacuation time decreased by up to 45% compared to that when the original route was used, and the time required decreased by up to 840 s. Hence, alternative routes must be derived according to evacuee congestion when the optimal evacuation route is calculated. Apart from considering real-time congestion, evacuation routes should account for the location of evacuees using technologies such as real-time indoor positioning;
- The limitations of this study are as follows: First, a single seismic scenario was considered and applied to a simplified two-dimensional structure with three basement floors. Second, variables that can lead to a reduction in the evacuation speed of evacuees, such as the mental state, obstructed vision, and obstacles, were not considered. Third, the personal characteristics of evacuees, such as children or people with a disability, were not considered. Fourth, this study only focuses on the effect of congestion on the evacuation time of all users during an earthquake and cannot consider the phenomenon of congestion level changes and the subsequent slowdown and recovery of evacuation speed. Finally, this study was conducted only for earthquake scenarios, which could limit the generalization of evacuation routes for other disasters such as fire and flood;
- In future research, it is necessary to apply the proposed congestion-based earthquake emergency evacuation simulation model to complex historical structures in three dimensions and to consider various variables, such as the evacuee’s state, the presence of obstacles, and a disaster-disadvantaged person, which can have an effect on evacuation speed. Also, the real-time congestion changes and the subsequent slowdown and recovery of evacuation speed should be considered in further study. After developing an advanced congestion-based evacuation model, the verification of the evacuation model should be conducted based on experimental data. It is also necessary to create an evacuation simulation model applying other algorithms, such as the A* algorithm and the genetic algorithm, and perform a performance comparison. Also, since the analysis was performed only for earthquake scenarios, further studies, such as quantification of speed reduction effect and route restriction, are needed to apply it to fires, terrorist attacks, and other disasters. The combination of congestion-based evacuation route models and real-time indoor positioning technologies can provide efficient and safe routing for evacuees within an integrated disaster management system, which could be a game-changer in reducing casualties in disasters.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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Basement 1 | Basement 2 | Basement 3 | Total (People) |
---|---|---|---|
1600 | 1400 | 2400 | 5000 |
Evacuation Factor | Evacuation Speed |
---|---|
Horizontal transportation (platform, concourse, corridor) | 60 m/min |
Vertical transportation (stairs, stationary, escalator) | 15 m/min |
Escalator | 36 m/min |
Case No. | Ground Condition | Input Acceleration (g) |
---|---|---|
1 | Left side 100 m vs. = 360 m/s Right side 100 m vs. = 150 m/s | 0.3 |
2 | Left side 50 m vs. = 360 m/s Right side 150 m vs. = 150 m/s | 0.3 |
3 | Left side 100 m vs. = 360 m/s Right side 100 m vs. = 150 m/s | 0.2 |
4 | Left side 50 m vs. = 360 m/s Right side 150 m vs. = 150 m/s | 0.2 |
Damage Index (DI) | Damage State |
---|---|
0 < DI < 1 | No damage (ds1) |
1 < DI < 1.4 | Minor damage (ds2) |
1.4 < DI < 2.3 | Moderate damage (ds3) |
2.3 < DI | Extensive damage (ds4) |
Evacuation Factor | Evacuation Capacity |
---|---|
Horizontal transportation (platform, concourse, corridor) | 80 persons/m × min |
Vertical transportation (stairs, stationary, escalator) | 60 persons/m × min |
Escalator | 120 persons/m × min |
Turnstile | 60 persons/min |
Start Node | Evacuation Route | Exit Node | Evacuation Time (s) | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
0 | 0 | 14 | 4 | 18 | 8 | 22 | 12 | 12 | 108.5 | ||
1 | 1 | 15 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 159.6 | |
2 | 2 | 16 | 6 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 536.6 |
3 | 3 | 17 | 7 | 21 | 11 | 23 | 13 | 13 | 417.4 | ||
4 | 4 | 18 | 8 | 22 | 12 | 12 | 72.32 | ||||
5 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 123.47 | |||
6 | 6 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 256.47 | ||
7 | 7 | 21 | 11 | 23 | 13 | 13 | 137.40 | ||||
8 | 8 | 22 | 12 | 12 | 42.32 | ||||||
9 | 9 | 8 | 22 | 12 | 12 | 93.47 | |||||
10 | 10 | 11 | 23 | 13 | 13 | 187.11 | |||||
11 | 11 | 23 | 13 | 13 | 62.8 | ||||||
Maximum evacuation time | 536.6 |
Start Node | Evacuation Route | Exit Node | Evacuation Time (s) | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
0 | 0 | 14 | 4 | 18 | 8 | 22 | 12 | 12 | 325.6 | ||
1 | 1 | 0 | 14 | 4 | 18 | 8 | 22 | 12 | 12 | 390.0 | |
2 | 2 | 1 | 0 | 14 | 4 | 18 | 8 | 22 | 12 | 12 | 890.0 |
3 | 3 | 17 | 7 | 21 | 11 | 23 | 13 | 13 | 1252.2 | ||
4 | 4 | 18 | 8 | 22 | 12 | 12 | 217.0 | ||||
5 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 370.4 | |||
6 | 6 | 7 | 21 | 11 | 23 | 13 | 13 | 545.3 | |||
7 | 7 | 21 | 11 | 23 | 13 | 13 | 412.2 | ||||
8 | 8 | 22 | 12 | 12 | 127.0 | ||||||
9 | 9 | 8 | 22 | 12 | 12 | 280.4 | |||||
10 | 10 | 11 | 23 | 13 | 13 | 561.3 | |||||
11 | 11 | 23 | 13 | 13 | 188.4 | ||||||
Maximum evacuation time | 890.0 |
Start Node | Evacuation Route | Exit Node | Evacuation Time (s) | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
0 | 0 | 14 | 4 | 18 | 8 | 22 | 12 | 12 | 325.6 | ||
1 | 1 | 15 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 479.0 | |
2 | 2 | 16 | 6 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 1609.8 |
3 | 3 | 17 | 7 | 21 | 11 | 23 | 13 | 13 | 1252.2 | ||
4 | 4 | 18 | 8 | 22 | 12 | 12 | 217.0 | ||||
5 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 370.4 | |||
6 | 6 | 5 | 19 | 9 | 8 | 22 | 12 | 12 | 769.8 | ||
7 | 7 | 21 | 11 | 23 | 13 | 13 | 412.2 | ||||
8 | 8 | 22 | 12 | 12 | 127.0 | ||||||
9 | 9 | 8 | 22 | 12 | 12 | 280.4 | |||||
10 | 10 | 11 | 23 | 13 | 13 | 561.3 | |||||
11 | 11 | 23 | 13 | 13 | 188.4 | ||||||
Maximum evacuation time | 1609.8 |
Case No. | Without Congestion Coefficient | With Congestion Coefficient—Original Route | With Congestion Coefficient—Alternative Route |
---|---|---|---|
Case 1 | 536.6 | 1609.8 | 890.0 |
Case 2 | 576.5 | 1729.6 | 1368.5 |
Case 3 | 809.1 | 1867.2 | 1514.9 |
Case 4 | 1138.2 | 2771.5 | 1931.4 |
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Yoo, M.; Haam, S.; Song, W.S. Congestion-Based Earthquake Emergency Evacuation Simulation Model for Underground Structure. Buildings 2024, 14, 3217. https://doi.org/10.3390/buildings14103217
Yoo M, Haam S, Song WS. Congestion-Based Earthquake Emergency Evacuation Simulation Model for Underground Structure. Buildings. 2024; 14(10):3217. https://doi.org/10.3390/buildings14103217
Chicago/Turabian StyleYoo, Mintaek, Sunnie Haam, and Woo Seung Song. 2024. "Congestion-Based Earthquake Emergency Evacuation Simulation Model for Underground Structure" Buildings 14, no. 10: 3217. https://doi.org/10.3390/buildings14103217