The Study Of Emergency Evacuation From A Room With Two Exits Based On Mice Experiment

Sufficient evacuation can reduce causality in emergencies.Rooms with two exits are universal in real life buildings.However,crowd behaviors such as clogging and uneven using of two exits may occur in emergencies.It is of practical significance to study emergency evacuation from two-exit rooms.Animal experiments can solve the problem of lacking real panic in pedestrian evacuation experiments in emergency evacuation study.Therefore,mice were used to study emergency evacuation from rooms with two exits.First,single-file movement and bottleneck experiments that widely used in pedestrian dynamic studies were carried out to study mice movement characteristics.In the single-file movement,the speed of mice increases rapidly with distance headway and then keeps stable with the free speed of 35.5cm/s.In bottleneck experiment,mice passed through the exit with bursts in different sizes,which obeys exponential distribution.The time gap between the two mice passing through the exit distributes with power-law tail.The piecewise linear dependency of velocity and distance headway and the phenomenon of mice passing through the exit intermittently are consistent with pedestrian movement results.However,mice show overlapping and crowding behaviors,which make their velocity decrease slowly with densities when ρn*>0.4 as well as the higher specific flow rate by compacting their bodies when passing through bottleneck.Then,mice emergency evacuation from a room with two exits in different locations was studied.Different utilization of the two exits was empirical proved.The exits on the adjacent walls get the highest evacuation efficiency.When it comes to the gap between exits on the same wall,the evacuation efficiency becomes worse with the gap between exits and then rises back and tends to be stable.Finally the exits are in the corner,and make the evacuation most efficient.The density and relative position of mice aggregation area in front of exits have effect on the evacuation.In addition,the phenomenon of mice changing paths and following others was observed.When the two aggregation areas obviously separated,mice follow,ing behavior promote the evacuation.Finally,the result of mice experiment was compared with social force model result,considering the difference of body shape and body size between mice and humans.The mechanism of emergency evacuation from a room with two exits in this study was summarized.When d=0,the evacuation efficiency of a wide single exit is lower than that of the two narrow exits,because mice could shrink their body when passing through narrow exit,and the simulation result is contrary.When the gap between two exits is less than about 2 times of body size,the aggregation areas in front of exits influence each other.The probability of intermittent clogging decreases slowly.Evacuation becomes worse with the increase of exit gap.When the gap between the exits is close to specific size of the pedestrian aggregation area R,the evacuation becomes efficient.When the exits are in the corner,the evacuation is optimal,while the reasons of simulation and experiment results are not completely the same.