Experimental Study On The Effect Of Trolley Case On Unidirectional Pedestrian Flow In Base Cases

In recent years,with the acceleration of the urbanization process,the pressure on transportation has increased dramatically.In transportation buildings,the number of pedestrians carrying luggage is large,the personnel gathering is frequent and the personnel movement is complex,which poses a high risk of safety.Moreover,in such buildings,special structures such as corridors,corners and bottlenecks are common,and the differences in the movement of crowd are very significant.Therefore,the impact of carrying luggage on pedestrian movement characteristics in based cases needs to be further discussed.In this study,aiming at the three base cases(straight corridor,corner and bottleneck),we explored the impact of the different ratio of pedestrians carrying trolley cases(RCT)on the unidirectional pedestrian flow and individual movement characteristics,through the controlled experiments.First,a controlled experiment was carried out on the effect of carrying a trolley case on unidirectional pedestrian flow through a straight corridor.Due to the following behavior,layer distribution was observed from the trajectories of the mixed pedestrian flow formed by the pedestrians with trolley cases and those without trolley cases.Besides,it was also found that pedestrians carrying the trolley cases would hinder the velocities of other pedestrians who did not carry the trolley cases.With the increase of the ratio of pedestrians with trolleys,the scatter plot of the data will move toward the lower density area of the fundamental diagram,the maximum specific flow rate will decrease,and the velocity and specific flow rate will be less affected by the density,as well.By comparing the individual velocities of pedestrians with trolleys to those without trolleys,it is shown that in a higher density corridor(RCT=0%:ρ>1.7 m-2;TCT=100%:ρ>1.0 m-2),the individual velocity can be significantly affected by the trolley case.The gender of pedestrians is found to have a little impact on their velocities whether or not pedestrians are carrying trolley cases in the study.Then,the influence of the ratio of pedestrians carrying trolley cases on the unidirectional pedestrian flow in the corner was investigated.Experimental results show that pedestrians are more inclined to find the shortest motion path in turning movement,the inner and middle regions of the right-angled corridor are used more frequently,and the peak of density often appears near the inner corner.In addition,the utilization rate of the outer region of the right-angled corridor increased with the increase of the density or the ratio of pedestrians with trolleys.We also observed that most pedestrians decelerate when approaching the corner,and the closer to the inner corner,the larger velocities drop.The velocity at the inner corner is about 0.5 m/s.Compared with the fundamental diagram before and after turning,we also convinced that in a certain density interval(RCT=0%:ρ<1.4 m-2;RCT=50%:ρ∈[0.6 m-2,1.9 m-2];RCT=100%:pE[0.7 m-2,1.8 m-2]),there is no difference between them.Finally,the effects of the bottleneck width and the ratio of pedestrians carrying trolleys on the unidirectional pedestrian flow through the bottleneck are discussed.According to the trajectories and spatiotemporal profiles,we analyzed the distribution of position,density and velocity.Results show that,in front of the bottleneck,the crowd contour is teardrop-shaped.And as the ratio of pedestrians with trolleys increasing,the peak value of density gradually decreases,and the position where it appears gradually deviates from the vertical line of the bottleneck and away from the entrance of the bottleneck.Furthermore,the number of pedestrians moving at a lower desired velocity in front of the bottleneck and pedestrians taking a detour and squeezing from the side boundary of the bottleneck increases,as well.Whereas,inside the bottleneck,there are stable pedestrian layers near the two sides of the boundary,and the densities and velocities are relatively constant(Rcr=0%:ρ=2.80 m-2,v=0.7 m/s;c7=50%:p=2.00 m-2,v=0.7 m/s;RCT=100%:ρ=1.20 m’2,v=0.7 m/s).As for the flow rate,the flow rate is linear related to the bottleneck width under different ratio of pedestrians with trolley cases.And when the ratio of pedestrians carrying trolley cases increases,the specific flow rate decreases.The results also show that the time interval between two adjacent pedestrians entering the bottleneck presents a power-law tail distribution.The smaller the bottleneck width or the greater the ratio of pedestrians carrying trolley cases,the greater the time interval.The outcomes can not only support the parameter setting and data calibration of the crowds carrying trolley cases in simulation,but also provide reference and inspiration for crowd management and pedestrian facility optimization during normal operation and emergency treatment of transportation buildings.