100m钢筋混凝土烟囱定向爆破拆除实践与数值模拟

Practice and Numerical Simulation of 100m Reinforced Concrete Chimney by Directional Blasting

为了顺利拆除复杂环境下100m高钢筋混凝土烟囱,针对该烟囱自身结构与烟囱周围环境特点选用梯形爆破切口并开设了定向窗与定位窗。经分析计算确定了切口圆心角为230°、切口高度2.5m;孔距0.35m、排距0.30m;单孔药量60g、炮孔总数522个;用MS1、MS3、MS5段毫秒导爆管雷管进行孔内毫秒微差起爆的爆破施工方案。对爆破振动、塌落振动、爆破飞石距离进行了安全校核并采取适当防护措施。通过LS-DYNA选取适当参数对该烟囱进行了1:1数值仿真模拟,模拟倒塌过程与实际倒塌过程基本一致,烟囱顶部触地时速度为22.8m/s,在烟囱的爆破拆除中,坍落振动比爆破振动影响大。起爆后经过11s该烟囱按预定方向顺利倒塌,未对附近建筑物造成影响。

In order to demolish the 100 m high reinforced concrete chimney in complex environment,according to the structure of the chimney and the characteristics of the surrounding environment of the chimney,the trapezoid blasting cut is selected and the directional window and positioning window are set up.Through analysis and calculation,the center angle of the cut is 230 and the height of the cut is 2.5 m,the spacing is 0.35 m and the row distance is 0.30 m,the single hole charge is 60 g and the total number of holes is 522.The blasting construction scheme of millisecond time delay blasting is carried out with MS1,MS3 and MS5 millisecond detonators.The blasting vibration,collapse vibration and the distance of flying rock are checked and the appropriate protective measures are taken.The chimney demolition blasting was simulated by 1∶1 numerical simulation using LS-DYNA by selecting appropriate parameters.The simulated collapse process is basically consistent with the actual collapse process.When the top of the chimney touches the ground,the velocity is 22.8 m/s.In the practice of chimney blasting demolition,the collapse vibration has a greater than the blasting vibration.After 11 s of blasting,the chimney collapses smoothly in the predetermined direction,without any impact on nearby buildings.