Research On Pressure Characteristics Of Competitive Crowds

Large scale activities often involve thousands of people,once improper management or unexpected incidents occur,it’s very easy to cause serious consequences of mass death and injury due to over-crowding.According to the survey,the force of squeezing in the crowd can be up to 4500N,while the pressure threshold of human body is between 2000-4000N,that is,the force produced by crowd may lead to pedestrian suffocation or death.At present,domestic and foreign scholars’research on the interaction between people is very limited,measuring pressure in a competitive crowd is difficult due to ethical issues.Therefore,this paper designs a set of armor protection device,which can not only protect their personal safety,but also measure the pressure imposed on them during extrusion or collision.First,this experiment designed two pushing modes.One is asynchronous push,volunteers stand in a queue and push forward according to their own rhythm;The other is synchronous push,volunteers push forward at the same time with the same rhythm.For asynchronous push,the 6 persons push can produce a maximum pressure of about 1710N,its empirical formula is fitted:F_max（n）=194.5（n-1）+196.6,the pedestrian can be seriously injured by the nonsynchronous push of 14 consecutive people.For synchronous push,the 6persons push can produce a maximum pressure of about 2806N,and fit its empirical formula:F_max（n）=314.5e*0.36（n-1）,and its force increases exponentially with the number of people,and the force of transmission and accumulation in the crowd is greater.Secondly,the pressure characteristics of people colliding along the queue at two different intervals of 0.10m and 0.15m are studied.Under the interval of 0.15m,the maximum pressure of 6 people colliding along the queue can be 1354.36N,and the empirical formula is fitted:F_max（n）=142.28e*0.37（n-1）,its force propagates along the queue almost exponentially,it will gradually accumulate beyond the threshold that human body can bear.The maximum pressure that can be generated at a distance of 0.10m is920.22N,and its formula is fitted:F_max（n）=153.14e*0.31（n-1）,and through comparison,it’s found that the greater the interval distance between personnel,the greater the value of force accumulation along the queue.Then,through the analysis,it’s found that the time interval of the first part of the personnel falling down basically presents a steep descent stage,and the time interval of the latter part of the personnel basically presents a stable stage.Finally,six different slopes（positive slope:5%、10%、15%,negative slope:-5%、-10%、-15%）are set to study the pressure characteristics of pedestrian collision along the queue on the inclined ground.It is found that the greater the proportion of negative slope,the greater the force produced by collision along the queue,while the greater the proportion of positive slope,the smaller the force produced by collision.The maximum pressure of 2079.18N can be generated when 6 people collide along the queue under the slope of-15%,and the empirical formula is fitted:F_max（n）=182.14e*0.42（n-1）,while the 15%slope can only produce the maximum pressure of 950.60N,and the formula of collision force under other different slopes are fitted at the same time.Then it is found that the larger the slope proportion is,the shorter the time interval is.