预拆除对薄壁双曲型冷却塔爆破拆除的影响

Influence of pre-demolition on blasting demolition of thin wall hyperbolic cooling tower

针对贵阳发电厂内冷却塔是由钢筋混凝土构成的薄壁双曲型圆筒,具有底部直径大,垂直高度高,塔壁外部没有施工条件且周边环境较为复杂的特点,采用预拆除技术,以确保冷却塔爆破拆除顺利实施并取得良好的效果。预拆除技术主要由3个部分组成:冷却塔内部支撑、倒塌方向薄壁的减荷槽以及倒塌反向的泄压窗。通过理论计算设计出正梯形爆破切口的参数,在人字形柱上同时采用开设减荷槽(13个)的方法,来保证冷却塔筒壁在倒塌过程中的屈服破碎效果,为了进一步减小爆炸冲击波对冷却塔筒壁的破坏作用,在倒塌方向的反方向开出一个2m×4m的矩形泄压窗。根据现场实验结果和冷却塔整体爆破效果,预拆除技术对薄壁双曲型冷却塔爆破起到了良好的作用,达到了冷却塔整体失稳倒塌,精确定向以及整体不下坐的效果。

The cooling tower in the Guiyang power plant is a thin wall hyperbolic cylinder composed of reinforced concrete and it has the characteristics of large bottom diameter,high vertical height,no construction conditions outside the wall of the tower.The surrounding environment is complex.In order to ensure the smooth implementation of blasting demolition and achieve good effect,pre-demolition technology is used.The pre-demolition technology mainly consists of 3 parts:the internal support of the cooling tower,the subtraction tank of the thin wall in the direction of collapse and the pressure relief window of the collapsed reverse.The blasting notch parameters are designed through theoretical calculations.13 load reducing slots are set up on a character shaped column to ensure the cooling tower wall yield in the process of collapsing in the crushing effect.In order to further reduce the damage effect of explosion shock wave on the wall of the cooling tower,a rectangular pressure relief window with 2 m×4 m is opened in the reverse direction of the collapse direction.According to the field test results and the overall blasting effect of the cooling tower,the pre-demolition technology plays a good role in the blasting of the thin wall hyperbolic cooling tower and the effect of the cooling tower's overall instability,collapse,precise orientation and overall sitting are achieved.