烟囱爆破拆除及其振动测试分析

摘要

By means of trapezoidal cut,the design of reasonable blasting parameters and the monitor of blasting and touchdown vibrations were conducted for the successful demolishing of reinforced concrete chimney of 41 m high.According to the analysis of vibration graphic,it takes about seven seconds from detonation to touchdown.Two different approaches to solving the vibration main frequency are introduced:The first frequency corresponds to maximum vibration velocity according to the GB standards,while the second frequency corresponds to maximum energy density and be achieved by Fourier transform.In spite of the great difference in calculation,both of them support the fact that the main frequency of blasting vibration is larger than that of touchdown vibration,and touchdown vibration frequency is more close to the inherent frequency of buildings,which is easy to lead to resonance.%针对41m高钢混结构烟囱爆破拆除,采用梯形缺口方式,设计了合理的烟囱爆破参数,并对爆破振动、塌落振动进行监测.通过分析振动图谱,得出烟囱从起爆到塌落共需7s左右.介绍了振动主频的两种求解方法,一种是国标规定的最大振动速度对应的频率;另一种是最大能量密度处由FFT分析快速傅里叶变换得到的频率.虽然两者之间存在较大差异,但都证明了爆破振动的主频要高于塌落振动的主频,塌落振动频率更接近于建筑物的固有频率,容易引起共振.