Simulation Of Directional Blasting Collapse Of Buildings And Study On Collapse Vibration Propagation Law

With the acceleration of modernization,blasting demolition is becoming more and more common in urban demolition projects due to its features of efficiency,speed,and economy.However,not only blasting vibration occurs at the moment of blasting,but also the contact-to-ground vibration generated during the collapse process Impact on the surrounding structures of blasting buildings to varying degrees.In order to investigate the law of structural collapse contact ground vibration propagation,the general finite element software ANSYS/LS-DYNA was used to restore the structural collapse process and vibration site.The main work contents are as follows:(1)Introduce the mechanical process of structural blasting demolition from the stable state to the unstable and collapsed state,and the possible harm caused by the vibration effect produced by the collapsing body;First Teaching Building of the Department of Engineering of Wuhan University and Erqi Riverside Business District of Jiang'an District The blasting demolition project was used as an example to analyze the main characteristics of ground vibration and compared with the previous engineering experience.It was confirmed that the collapse vibration during the collapse process had a greater impact on the surrounding buildings than the blasting vibration,and the measured speed of the collapsed vibration was different in three directions.The difference between the component and the predicted value is large;(2)Determine the vibration site parameters,select the appropriate artificial boundary,establish the collapsed vibration field model,and compare the collapsed elastic foundation with the rigid foundation model.Although the elastic vibration site model requires a long calculation time,it can obtain a more reasonable result of the ground vibration velocity,which can be used as a research basis for structural collapse contact vibration propagation.(3)Taking the teaching building of Wuhan University as an engineering example,use ANSYS/LS-DYNA to build a numerical model of the building and site,and control the failure of components to achieve the collapse process of the structure,and compare it with engineering examples through collapse process,collapsed state,PGV,etc.,verify the authenticity of the finite element simulation;(4)Taking into account the differences in the form of propagation between in-situ collapse and directional collapse,and Zhou Jiahan's prediction formula for ground vibration velocity is more in line with the situation of in-situ collapse.Therefore,the various components of directional collapse vibration impact will be analyzed in this paper.Combining finite element simulation and engineering data qualitatively gives a general rule qualitatively,that is,for the case of a directional collapse in an actual blasting project,it is necessary to pay more attention to the horizontal vibration along the collapse direction;to set vibration isolation in the direction of the strongest impact vibration effect.Ditch,and change the position or depth of the vibration isolation groove to achieve the best vibration reduction effect.Increasing the depth of vibration isolation trenches has a better effect on ground vibration attenuation,but its effect is no longer obvious;vibration isolation trenches can effectively reduce the horizontal vibration of horizontal collapsing along the collapse direction,followed by vertical vibration.