Numerical Evaluation Of Blast Wall On The Protection Of Unreinforced Masonry Wall Against Blast Loading

In recent years,terrorist bombings and explosions caused by dangerous chemicals have occurred from time to time,causing a large number of casualties and serious damage to structures.Therefore,it is urgent to protect the structure through corresponding measures to avoid damage and collapse to the structure.The blast wall as the protective layer of the structure can change the propagation path of the shock wave and reduce the explosion load acting on the target structure,so that the structure and the occupants can be effectively protected from the threat of explosion.This paper takes the unreinforced masonry wall as the research object,and analyzes and studies the protective effect of the blast wall on the unreinforced masonry wall.The main research work and results are as follows:(1)Use the finite element software AUTODYN to analyze and calculate the explosion load on the unreinforced masonry wall behind the blast wall.In the calculation process,the blast wall and the unreinforced masonry wall are regarded as rigid elements.There are three factors to consider: the charge weight of the TNT,the location of the blast wall,and the height of the blast wall.(2)Use the finite element software LS-DYNA to calculate the dynamic response of unreinforced masonry walls under blast loads.In the calculation process,in order to save the calculation time,the uncoupled approach is adopted,that is,the pressure-time history curve of the surface of the unreinforced masonry wall obtained in AUTODYN is directly applied to the numerical model in LS-DYNA,to obtain its dynamic response.According to the damage of the wall,unreinforced masonry walls can be divided into four failure modes: severe damage,moderate damage,minor damage and no damage.The research results show that compared with the state without blast wall,the existence of blast wall at any position and height can attenuate the air shock wave,thereby reducing the damage of air shock wave to the wall.(3)Through parameter analysis,the influence of boundary conditions,height and position of blast wall on the dynamic response of unreinforced masonry wall is studied.The results show that with the increase of the height of the blast wall,its influence on the air shock wave increases,so the higher the blast wall,the better the protection effect;the boundary conditions also have a greater impact on the unreinforced masonry wall.The damage found tends to be smaller than that of one-way walls,so two-way walls are more resistant to explosion than one-way walls.