Experimental And Simulation Study Of Pedestrian Flow Considering Obstacle And Emergency Stop Behavior

With the acceleration of China’s urbanization process and the improvement of people’s living quality,large-scale crowd gathering activities have become increasingly frequent.Space isolation facilities and obstacles can be seen everywhere in various personnel activity places,but unreasonable layout of isolation facilities will affect the movement efficiency of pedestrians,and may seriously affect the life safety of pedestrians when confronted with emergencies.In addition,in the process of movement,pedestrians may temporarily stop because of picking up lost objects and tying shoelaces,etc.,which will form obstacles to the rear pedestrians and can also be regarded as temporary obstacles to some extent.Compared with the influence of space fixed obstacles,this kind of emergency stop behavior brings more potential dangers to pedestrians.When the crowd is dense,pedestrians behind are likely to fall over because they cannot get out of the way in time,which in turn causes a chain effect of dominoes,and eventually leads to a disaster such as a stampede.In order to deeply understand the impact of obstacles and emergency stop behavior on pedestrian movement,we used the method of combining experiment and simulation to study the movement behavior of researchers.The research results can provide a reliable basis for the design of pedestrian traffic facilities and the management of dense crowds.According to the purpose of the study,we recruited a total of 106 volunteers and set up 8groups of controllable pedestrian flow experiments to analyze the influence of obstacles and emergency stop behaviors on one-way pedestrian flow movement and onward pedestrian flow movement respectively.The main conclusions of this paper are as follows:(1)In the controlled experiment of one-way pedestrian flow,when there is no obstacle,the target deflection Angle of the pedestrian changes with the position as a periodic wave,which is caused by the natural swing of the pedestrian body during movement;In the experiment with obstacles,different pedestrians have different reactions to obstacles.Some pedestrians will start to change their direction of travel to avoid obstacles when they are far away from the obstacles.Such pedestrians have small target deflection Angle,continuous movement trajectory changes and fewer mutations.Some pedestrians begin to avoid obstacles when they are very close to them,and the target deflection Angle of such pedestrians will change in a short distance and a short time.Through the study of emergency stop behavior,it is found that the first person behind the emergency stop pedestrian is most affected by the emergency stop behavior,and the speed will decrease sharply before the emergency stop position,which has a huge safety hidden danger.The number of pedestrians affected by emergency stop behavior increases non-linearly with the increase of emergency stop time.However,as the emergency stop time continues to increase,subsequent pedestrians will regard emergency stop behavior as a fixed obstacle,and the distance to avoid collision gradually increases.From the perspective of the impact of different emergency stop positions on pedestrians,when pedestrians have the need to temporarily stop,the location near the edge of the passage has the least impact on others.The impact of emergency stop behavior on pedestrian speed varies greatly under different crowd density.When the crowd density is small,the impact of emergency stop behavior on pedestrian speed is not obvious.However,both fixed obstacles and the existence of emergency stop behaviors reduce the average speed of pedestrians,which indicates that most pedestrians will reduce their speed when they encounter obstacles,so as to ensure their safety.(2)In the contralateral flow control experiment,the existence of obstacles will break the original hierarchical structure of pedestrians,which is not conducive to the rapid movement of pedestrians.In the movement of people in the opposite direction,the performance of the pedestrian in the first place in the queue is extremely critical,which will greatly affect the overall movement performance of the pedestrian column to which it belongs.Boys are more active and have more walking advantages when facing the intersection.Fixed obstacles will disperse the longitudinal displacement difference of pedestrians,which further confirms that the existence of obstacles will interfere with the formation of pedestrian stratification.Pedestrians moving in the opposite direction will always have an advantage at the intersection,but the density fluctuates greatly during the intersection,and the speed always decreases until the intersection pedestrians separate.However,emergency stop behavior does not break the hierarchical structure of pedestrians.After the impact of emergency stop behavior,pedestrians in the queue of emergency stop will seek for free space in the channel,and gradually recover their motion speed,or even exceed their previous motion speed.The extent to which the queue adjacent to the emergency stop queue is affected by the emergency stop behavior is related to the number of pedestrians shunting the emergency stop queue,and the pedestrians on the right side of the emergency stop queue are often affected more.In the study of the pedestrian entry mode,it is found that the pedestrian stratification is more stable when entering on the right side,and the time spent walking in the passage will be greatly reduced.(3)The traditional social force model is used to simulate the one-way pedestrian flow,which can better reproduce the phenomenon of pedestrian self-organization.However,the social force model can not reproduce the micro-motion behavior of pedestrians in the process of movement very well,so it needs to be improved.