Numerical Analysis And Design Method Of A New Fence Type Blast Wall

Based on the principle that wave reflection,diffraction and interaction can weaken the energy of blast wave,some scholars proposed a new fence type blast wall composed of a number of structural poles.The protective effectiveness has been verified by 2D numerical simulation and field tests.For this new fence type blast wall,3D numerical research has been carried out in three aspects.1.Comparative analysis of fence type and RC blast wallsThe correctness of the RC model and fence type blast wall model is validated by comparing the results of numerical simulations and field tests.Two types of blast walls are analyzed.It is found that the fence type blast wall could reduce the overpressure and impulse up to 70% if properly arranged.Fence type blast wall could perform equally or even better than the RC wall in mitigating overpressure and impulse.Moreover,fence type blast wall is free from the secondary debris hazards under closein explosion.2.Parametric analysis of protective effectiveness of fence type blast wallBased on the results of 2D numerical simulation and field test,further 3D numerical study is carried out.The optimal configuration of fence type blast wall is obtained by parametric analysis of different section forms,pole spacing,barrier layer number and the spacing between layers.When the poles in the back layer is staggered to the front layers,the protective effectiveness of the fence wall is the best.The results of numerical simulation show that smaller spacing between poles and more layers of the fence type blast wall lead to better protective effectiveness.When the C/φ is 2,the fence wall has better protective effectiveness.However,many factors need to be considered to determine the configuration of the fence wall.3.Fitting the formulas of pressure and impulse on the surface of the buildingA full-scale 3D model of air domain and fence type blast wall is built.According to the results of numerical analysis and to meet the requirements of construction and protection,the arrangement of fence type blast wall is determined.The important parameters,including building high,TNT explosive equivalent,the distance from initiation point to the wall and the distance form initiation point to the building,affecting the protective effectiveness of fence wall and the surface load on building are analyzed.The formulas of pressure and impulse on the surface of building behind the fence wall are fitted,which provides the basis for the evaluation of the explosion load on the building after the fence type blast wall.