Study On Dynamic Response And Safety Protection Of Underground Structure Column Under Explosion

With the rapid development of modern cities,the rational development and utilization of underground space has become an inevitable trend.However,the enclosed environment of the underground structure and the variability and uncertainty of the load on the structure will cause serious damage to the structure and people once the internal explosion occurs.Therefore,it is especially important to pay attention to the shock wave propagation law and dynamic response of underground structures under explosive loads.In this paper,the ANSYS/LS-DYNA finite element software is used to establish the fluid-structure coupling model of reinforced concrete columns under explosive load,respectively to simulate the dynamic response and anti-explosion effect of the column under different conditions,and to the surrounding personnel through the distribution of overpressure Damage prediction.The main research content and results include:(1)Taking the reinforced concrete column in the underground shopping mall as the research object,a typical structure-air-explosive fluid-structure coupling model is established to study the dynamic response and shock wave propagation law of the column under internal explosion.The study found that in the early stage of explosives,the stress distribution on the cylinder will appear obvious "stratification" phenomenon,with the passage of time,the dynamic response of the cylinder becomes complicated,both ends of the cylinder and near the edge of the square cylinder Stress distribution is relatively concentrated and needs to be focused on.(2)The dynamic response of the cylinder to internal explosion under different explosive amounts,distances and column forms was studied respectively.The study found that with the increase of the explosive amount,the peak stress everywhere will also increase,and the increase rate will slow down;as the distance increases,the peak stress at each point will continue to decrease,and the rate of decrease Compared with a square column,the stress distribution on each reference line node is more uniform and smaller than the square column,and the stress peak is smaller,and the side of the column is safer than the square column.(3)The anti-explosion protection effect of the steel plate protective layer added to the cylinder on the explosive was studied.By establishing the coupling model of the external protective layer,the stress distribution and the degree of damage on the two columns without the protective layer were compared.Analysis shows that the addition of a steel plate protective layer can play a good role in explosion protection.(4)The evaluation criteria for casualties under the impact of explosions at home and abroad were analyzed.Evaluation criteria for different injury levels were established based on safety regulations and overpressure criteria,and the reliability of the overpressure criteria was verified.The overpressure at each position of the column was used peak value predicts the safety distance of people under different injuries.