Study On Upward Evacuation Model Of Underground Multi-level Personnel Concentrated Places Considering The Influence Of Visibility

With the gradual advancement of China's urbanization process,the city's land resources are gradually scarce,and the underground space has become increasingly prominent in the development of human society.In order to save space and realize the complex and diverse functions of the building itself,in addition to raising the height of the building,the underground part of the building is deeper and deeper.However,the existing evacuation models at home and abroad mainly focus on the development of down-and-level evacuation of ground buildings,and can not show the synergistic effect of factors such as fatigue and visibility on the ascending evacuation speed of underground multi-layered personnel.That is to say,in view of the randomness of fire incidents and the complexity of personnel behaviors,it is not enough to study the evacuation process of underground multi-layer personnel in the underground.Therefore,the research on the model of ascending evacuation of underground multi-layered personnel in consideration of visibility impact has a rich theoretical and practical significance.Firstly,based on the multi-velocity cellular automata evacuation speed model of fine mesh,an uplifting model of underground multi-level personnel dense places considering the influence of visibility is constructed.Then,the data of the evacuation experiments carried out by the research group are analyzed and analyzed.Three kinds of different evacuation simulations are carried out by using the constructed model.The evacuation of people under different visibility conditions is compared and analyzed.The influence of visibility on the evacuation process and evacuation results is studied..Then,the evacuation experiment data and the evacuation simulation results of the same experimental scene are compared and analyzed,and the four-dimensional trajectories of the experimental data and the evacuation simulation are compared and analyzed to find out the reason for the deviation between the simulation and the experiment.The main results are as follows:(1)Visibility is one of the important influencing factors affecting the evacuation speed of underground multi-layered personnel.As visibility decreases,the evacuation speed decreases and the evacuation time is longer.In the evacuation simulation under the influence of visibility,under normal conditions,the outlet flow rate is 0.43 ped/(ms),the evacuation completion time is 2286.5 s,and the exit flow rate is 0.23 ped/(ms)under the effect of 27%visibility,which is reduced.46.5%;total evacuation time was 4239s,an increase of 85.4%.The outlet flow rate was 0.18 ped/(ms)with a 16%visibility,which was reduced by 58.1%;the total evacuation time was 5612 s,an increase of 145.5%.It has also been found that the exit flow rate is proportional to the expected speed of the person(when the person expects the speed to be constant).(2)In the evacuation experiment,the distribution of the ascending evacuation time of the 27%and 16%eye masks was 193~323s and 269~352s.Under the simulated conditions,the uptime of the 27%and 16%eye masks was 223~310s.And 283~356s.As the visibility decreases during the evacuation process,the evacuation time increases gradually.The relationship between the cumulative number of exits and the evacuation time of simulation and experiment is relatively consistent.(3)For the personnel wearing 16%eye mask conditions,the established evacuation model has certain feasibility.For the person wearing the 27%eye mask condition,the static field sensitivity coefficient K_S and the model input speed are not the main factors affecting the deviation of the evacuation trajectory,which indicates that the deviation is caused by other reasons.(4)The technique of extracting evacuation trajectory by using image data makes the verification of the evacuation model to a new level.By extracting the experiment and simulating the evacuation trajectory points of the personnel during the evacuation process,the trajectory points are digitized and visualized,and the contrast experiment is carried out.And the evacuation simulation consists of a four-dimensional trajectory consisting of position and time.The obtained evacuation data can not only verify the accuracy of the evacuation speed and evacuation time of the experiment and simulation,but also verify the evacuation rate of the evacuation trajectory and further verify the behavior of the model setting.The rationality of the rules.