Analysis Of Train Station Casualties And Preventive Strategies In View Of Explosion Attacks

At present,terrorist activities are increasingly rampant and have caused very bad effects in the international community.Among them,explosive weapons have become the most common attack method because of their flexible use,simple production,high lethality and strong destructive power.As an important national infrastructure and transportation hub,the railway station has the characteristics of dense crowds and large mobility.The terrorists are easy to hide and easy to transfer after launching attacks,which makes them easy to be the terrorist attack targets.Relying on a railway station terrorist attack risk assessment project,this article studied the explosive terrorist attacks at the railway station.Since the railway station is equipped with security equipment,the explosives can hardly enter the explosives directly.Therefore,the most intensive railway station subway transfer area was studied as a research object for its lack of security measures and high personnel density.The LS-DYNA finite element analysis software was used to simulate the explosive terrorist attack in the area and the casualties.Then the prevention strategies for terrorist attacks,were put forward.As the target area is oversized,this study used a mesh generation method with unequal spacing and segmented switching mesh size and simulated the loading of 44 kg,22.53 kg and 13.04 kg respectively.Then the flow field distribution and casualty radius of shock wave in underground transfer area were obtained,and the relationship between different postures and casualty radius was analyzed.According to the experiment,when an explosion occurs in underground space,the influence range of the shock wave significantly expands,and the area of casualties extends to 150 meters beyond,which is much larger than the action range of the blast wave in open space,and the larger the equivalent,the larger the radius of casualties.The shock wave reflects violently near the walls on both sides.The over-pressure of the reflected wave is greater than that of the incident wave.When the over-pressure time history curve of the measuring point transitions from the walls on both sides to the middle area,the over-pressure of the reflected wave peak value decreases gradually.The human body's different postures also have an effect on the casualty radius.The casualty radius of the prone position is small within a range of 3.6m near the explosion source.However,after the distance of 20 m,the casualty radius of standing posture is smaller.According to the experimental results and site elements,this paper proposed the strategies of preventing explosive terrorist attacks in underground transfer area so that the railway station and similar sites can use them to strengthen the protection in the weak areas of underground security inspection.