Numerical Simulation Research And Application Of Factors Affecting The Collapse Accuracy Of Ultra-high Steel Concrete Chimney

The ultra-high reinforced concrete chimney has large volume and weight,and the collapse mechanism of blasting demolition is complex.The scheme design mainly depends on the empirical formula,so the collapse accuracy of chimney is difficult to guarantee,and the accuracy and safety of blasting demolition still need to be improved.With the popularization of numerical simulation technology,more and more engineers and technicians apply it to demolition blasting industry.The main content of this paper is to take an ultra-high reinforced concrete chimney blasting demolition project as the research object through the theoretical calculation of the key parameters of the chimney blasting cut,and using the finite element method combined with ANSYS/LS-DYNA software to carry out the instability analysis and collapse process simulation of the steel concrete chimney,the main research results are as follows:Based on the theory of material mechanics and engineering blasting,two key parameters of blasting notch angle and height of steel concrete chimney are analyzed and calculated by using stress failure criterion and bending moment failure criterion respectively.On the basis of theoretical calculation,the instability model of super-high chimney blasting demolition is established by using ANSYS/LS-DYNA,and the collapse effect of eight different blasting incision angles is simulated.The sitting down speed,forward distance and deviation angle of chimney are analyzed.The results show that when the blasting incision angle of chimney is 215 ° The results are in good agreement with those based on the stress failure theory.ANSYS/LS-DYNA software is used to simulate the influence of delay time error of 180 m chimney blasting incision on its collapse accuracy.When the delay time error of corresponding parts on both sides of blasting incision is 50 ms,the deflection angle of the cylinder increases by 3.76 times.Based on the numerical simulation of the vibration reduction effect of the damping earth dike and the damping ditch,the blasting demolition model of a 180 m chimney is established.The results show that the damping earth dike and the damping ditch have a significant effect on reducing the vibration of the chimney,and the peak value of the ground particle vibration velocity can be reduced up to 76.1%.On the basis of theoretical calculation and numerical simulation,the blasting scheme of a 120 m reinforced concrete chimney is designed in detail.The expected blasting effect is successfully achieved through accurate calculation of incision parameters,taking safety protection measures such as piling shock absorption embankment and excavating shock absorption ditch.The research results show that the theoretical calculation combined with numerical simulation can comprehensively and deeply analyze the notch parameters,collapse process and collapse vibration effect,which is of great significance for the precise control and demolition of ultra-high reinforced concrete chimney.Figure[59]Table[14]Reference[81]...