框架结构楼房爆破震动响应的数值模拟

为研究框架结构在爆破震动下的震动响应特性,利用ANSYS/LS-DYNA显示动力分析软件,对某框架结构进行了模态分析与动力响应分析。得到了该建筑结构的自振频率小于10 Hz,低频爆破地震波是引起结构振动、变形的主因;对结构受距离20 m基坑爆破的振动影响进行了模拟,计算所得的距爆源最近点震速和实测震速基本吻合;分析了建筑结构不同楼层的爆破振动规律,表明建筑结构的垂直向速度响应大于水平向速度,20层的高层建筑结构随着楼层高度增加,在1~6楼出现了振动速度局部放大现象。裙楼楼顶(距爆源最远处)出现整个结构最大速度峰值。在城市复杂环境进行爆破施工时,对周围建筑结构的安全监测,不能只对距爆源最近地表进行振动监测,须注意高层建筑结构内部的局部放大效应。

Numerical Simulation of Blasting Vibration Response of Structure Building Framework

In order to study the vibration response characteristics of the frame structure under blasting vibration, the modal analysis and dynamic response analysis of a frame structure were carried out by using ANSYS/LS-DYNA display dynamic analysis software.The natural frequency of the building structure is less than 10 Hz,low frequency blasting seismic wave is the main cause of structural vibration and deformation;the vibration influence of structure under 20 m excavation blasting was simulated,and the calculated results are in agreement with the measured veloci-ty.The blasting vibration law of different floors of the building structure is analyzed and it is indicated that the verti-cal velocity response of the building structure is greater than the horizontal velocity.The 20-storey high-rise building structure increases with the height of the floor,in the 1~6 floor there has been a local vibration amplification phe-nomenon.The peak speed of the whole building appeared at the roof of skirt building which was farthest from the blasting source.When blasting construction under the complex city environment is in progress,not only the surface vibration near the blasting source needs to be monitored,but also the local amplification effect of the high-rise build-ing structure needs attention.