冷却塔爆破拆除塔壁触地解体规律研究

Study on Disintegration Law of Cooling Tower Wall Touching Ground by Blasting Demolition

针对爆破拆除冷却塔倒塌过程中的偏转形态与钢混材料破坏之间的关系,采用最大线应变理论方法建立关于母线L的函数表达式,利用LS-DYNA软件模拟倒塌过程中对材料设置多因素破坏条件,据此分析塔体在触地碰撞瞬间结构体的破碎位置及塑性铰转角极值[θ]。研究表明:除切口处塔壁发生破碎外,上部塔壁也发生破碎,且截面破碎位置在倒塌方向两侧;破碎截面随塑性铰转角极值增大而减小,上部塔壁截面破碎高度降低,当塑性铰转角极值达到3°时,塔壁仅在切口处发生破碎;增设剪应力失效阈值控制人字柱材料破坏条件,模拟倒塌效果与实际过程一致,证明采用最大线应变理论分析结构倒塌特征的准确性。

Regarding the relationship of the deflection pattern and the concrete-steel mixed material failure during the blasting demolition of the cooling tower,based on the maximum linear strain theory,a function expression about generator L is established to analyze the structural fracture location and the extreme value[θ] of the plastic hinge angle when the tower is contacting with ground.Besides,multi-factor damage conditions are set up when using LS-DYNA software to simulate the collapse process.According to the study,the incision of tower is broken as well as the upper tower wall,and the sectional fractures locations are distributed in both sides to the collapse direction.The fracture section decreases as the extreme value of the plastic hinge angle increases,with the reduction of the height of the fracture section in upper tower wall,and when the plastic hinge angle reaches 3°,only the incision of tower wall is broken.When adding shear stress failure threshold to control the damage condition of herringbone material,the simulated collapse effect is consistent with the actual process,which proves the accuracy of the maximum linear strain theory to analyze structural collapse characteristics.