Numerical Simulation And Optimal Analysis For Demolition Of Bridge Under Controlled Blasting

At present, the momentum of highway transportation infrastructure development are easing, the new projects are gradually replaced by reconstructions in the engineering market, while the market demands for bridge demolition is growing. However, the control blasting demolition method, as the most commonly used removal method, whose theory researches are lagged behind the practice seriously, leading to the blasting accidents occurred occasionally.If the whole process of bridge collapse under blasting can be visually predicted with the help of sophisticated computer numerical simulation technology, the restriction of the empirical formulas will be broken down, more targeted blasting design optimization scheme and construction safety protection scheme will be put forward as well. In order to promote the leap from extensive design to fine, the following researches were made:First, commonly used technical means of blasting in bridge demolition are summarized, the basic models of bridge collapsing are studied, the simplified theoretical mechanics model are made for analyzing the main factors that influence the blasting gap parameters.Secondly, considering that blasting demolition belongs to the sort of explicit dynamic question, the multi-software combined modeling method which based on the LS-DYNA solver is put forward.Then, according to the behavior during the collapse process, the appropriate element types and material models are selected, the control parameters of material failure, collision and calculation method are determined.Next, the method mentioned above was used to analyze two typical examples in bridge control blasting demolition project—the high pier to be demolished by blasting in the limited space and the arch bridge to be demolished by multi-stage blasting with one-time collapsed.Finally, according to the collapse video, the rationality of the parameters on the cut(position, length, height) and ignition order and time-delay gap was evaluated, the corresponding gap optimization scheme and safety construction measures were put forward.The results show that the bridge collapse blasting process simulation as expected, collapsed posture, blasting clinker size and of form can be multi-angle in parts observed, visually forecast was realized which leading to promotion of the innovation and diligence of blasting technology and have guiding significance for the implementation of the bridge blasting demolition.