主裙楼一体结构纵向倒塌拆除爆破技术

Demolition Blasting Technology for Longitudinal Collapse of Integral Structure of Main and Annex Building

在楼房爆破拆除中,针对包含裙楼(长宽比1)、办公楼(长宽比2.9)、两栋住宅楼(长宽比1.4)的复杂钢筋混凝土结构楼房按要求纵向倒塌的情况,采用底部裙楼排间立柱爆破分步延时间隔的方式使长宽比较大的办公楼在重力作用下从中部剪切分为两部分,楼体重心较易移出楼体外侧,同时通过高速摄像机研究结构破坏时间、过程并证明此方法的可行性。当排间立柱采用半秒延时导爆管雷管时,末排柱子与邻排柱子的合理延时间隔时间为200~300 ms左右,并应对切口最高处对应末排柱子的位置进行爆破弱化,以提高倒塌的可靠性。实际爆破中发现由于裙楼爆破后重心高度的上移有必要提高先爆楼体爆破切口的高度,且采用平切口的形式。针对地下室空气喷出造成的飞石提出解决措施,为今后类似爆破工程提供思路。

A complex reinforced concrete structure building including an annex building(length-to-width ratio=1),an office building(length-to-width ratio=2.9)and two residential buildings(length-to-width ratio=1.4)were required to collapse longitudinally by demolition blasting.The office building with large length and width was sheared into two parts step by step from the middle part under the action of gravity by means of delayed blasting between the rows of columns in the annex building.In this case,the center of gravity of the building was easier to move out of the outside of the building.At the same time,high-speed cameras were used to study the failure time and process of the structure and prove the feasibility of this method.When half-second delay detonators were used for the columns,the reasonable delay time between the last row of columns and the adjacent row of columns was about 200~300 ms.The highest point of the incision corresponds to the position of the last row of columns should be weakened by blasting to improve the reliability of collapse.In actual blasting,it was found that it′s necessary to increase the height of the blasting cut of the first exploded building due to the upward shift of the height of the center of gravity after the annex building blasting,and the form of flat cut was adopted.The countermeasures for flying rocks caused by air ejection in the basement were proposed to provide reference for similar blasting projects in the future.