| In recent years, the evacuation of pedestrians in large public places has received growing concerns of researchers. Unlike the road traffic flow, pedestrians will behave many unique features in the process of evacuation, such as diversity, randomness and self-organizing, and these features result in the pedestrian evacuation process extremely complex and risky. Therefore, it is very useful for managers to make make a further investigation on the pedestrian evacuation dynamics, including the macroscopic characteristics of pedestrian flow and individual’s microscopic characteristics. Making scientific evacuation strategies and effective controlling policies are the keys to improve evacuation performance and reduce the accidents. Through the in-depth analysis of different moving behaviors in different scenarios, a block-based floor field model is proposed in this paper. Through simulations, this paper makes further analysis and discussion on the moving trajectory of pedestrians, evacuation dynamics, the regularity of evacuation and the evacuation time in various kinds of scenarios. The simulation results will have important practical values in the optimization and evaluation of the channels and improving the management of crowd evacuation in large public places. The main works and innovations of this paper are as follows:1. Based on the detailed analysis of some existing pedestrian evacuation experiments, this paper studies the microscopic moving behavior of pedestrians in three typical scenarios (the Channel, Node and Bottleneck scenarios). Then it gives four basic types of blocks:the Channel Block (CB), the Turning Block (TB), the Buffer Block (BB) and the Bottleneck Block (BoB). Combined with the related knowledge of potential field theory, an effective method is established to calculate the static floor field within different types of blocks and it lays theoretical foundation in the successive chapters. The calculation precision is improved and the cumulative error is reduced by using this method. Block divisions minimize the accumulated error in the pro cess of potential calculation and achieve more precise numerical results2. Aiming at three typical kinds of Node scenarios:L-type, diverging and converging T-type scenarios, a block-based floor field model is presented to efficiently describe the pedestrians’ different dynamic features in different scenarios. In the model, block divisions are based on scenario geometries and pedestrian flow characteristics. Within each block, the static floor field is separately defined, and a boundary rule is incorporated in the model to deal with the connecting adjacent blocks. The simulation results show that the proposed model can well reproduce the empirical pedestrian’s moving behavior in the Node scenarios, i.e., pedestrian may transfer to the outer side of corner instead of queuing up at the inner corner when congestion happens, the moving trajectory and evacuation dynamics of pedestrians can be obtained and consistent with the actual. Pedestrians are more uniformly distributed in the whole evacuation process and the total evacuation time could be reduced due to fully utilized of scenarios for both channel and corner.3. A serious of simulations in typical Bottleneck scenarios have been carried out to investigate the performances of the block-based floor field model. The model is validated by the features of moving behavior of pedestrians through the bottleneck. According to the simulation results, it can be seen that the proposed model can well reproduce the empirical pedestrian’s moving behavior through the bottleneck and improve the distribution of pedestrians reasonably. By changing the relavant parameters, the proposed model can simulate pedestrians’trajectories conform to reality better. Moreover, the width of bottleneck is one of the important factors affecting the evacuation efficiency:the larger the width of bottleneck, the bigger the capacity is, and the evacuation efficiency is improved correspondently. |
PDF Full Text Request