高烟囱爆破拆除倾倒折断力学分析

针对150 m以上高烟囱在爆破拆除过程中频繁发生空中折断的现象，按照国内烟囱设计规范1]，选定相应烟囱结构设计参数，通过建立高耸钢筋混凝土烟囱在爆破拆除定向倾倒过程中的力学模型，推导了任一时刻烟囱任一截面的内力分布表达式和极限承载能力表达式，分析了其破坏机制。根据所受的荷载和承载能力对烟囱倾倒过程中是否会发生空中断裂进行了判断，结果表明，高度超过150 m的钢筋混凝土烟囱在倾倒角度超过40°～60°后，均可能在离顶部约1/3烟囱高度处发生断裂。

Analysis of fracture mechanics for falling tall chimneys during demolition blasting

In order to explain the frequent phenomenon that tall chimneys with a height more than 150m always fracture during falling process during demolition blasting, a mechanical model of tall reinforced concrete chimneys is set up in the directional falling process through the appropriate structural design parameters selected in accordance with the design standard of chimneys. The inner force distribution and limit bearing capacity expressions of chimney section at any time are derived; and the failure mechanism is analyzed. And then the evaluation is carried out if chimneys will fracture or not during demolition blasting according to its load and section strength. Results show that tall chimneys with a height more than 150 m will fracture at the section to the top 1/3 height when the tilting angle reaches to 40°-60°during demolition blasting.