为了避免和预防楼房爆破拆除出现后坐而造成的危害,根据建筑物爆破拆除过程中常出现的后坐现象,总结出3种基本形式:楼房倾而不覆;楼房虽倾覆,但解体和爆破效果差;楼房倾覆,但后坐严重,破坏了需要保护的建(构)筑物.结合高大凹型结构、重心偏离中心线楼房的爆破案例,对楼房爆破拆除的后坐现象进行了分析,产生后坐的原因有结构分析不彻底、延时时间设置不当等等.为此,提出了特殊切口、降低局部强度、控制楼房塌落倾斜加速度、改变起爆方式、减小支撑体与紧邻前部的延时时间等相应的解决措施.爆破案例的爆破效果说明了预防楼房爆破后坐必须从爆破方案设计开始,对整个爆破过程进行周密的预见性分析.分析结果对今后类似楼房的爆破拆除具有借鉴意义.%In order to avoid and prevent the damage caused by the backward collapse of buildings demolition blasting, according to the phenomenon of backward collapse during the building demolition blasting,three basic forms are summarized:buildings tilt but not collapse;although the building is collapse,disintegration and blasting effect is not better;the building is tilt but the backward is seriously,the buildings (structures)that needed protection is destroyed.In combination with a blasting case that large concave structure and the center of gravity deviates from the centerline building. The backward collapse phenomenon of building demolition blasting is analyzed.The reason for the backward collapse is that the structural analysis is not thorough,and the delay time is set incorrectly.So,special incisions is used,local strength is reduced,the collapse acceleration of buildings is controlled,the way of initiation is changed and reducing the delay time between the support body and the immediate front,etc.The blasting effect of the case shows that the prevention of building backward must begin with the design of the project.The entire blasting process predictive is analyzed.The analysis results have implications for demolition of similar buildings in the future.
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