钢筋混凝土结构爆破地震响应频谱及幅值变化规律分析

Spectral analysis and amplitude varying for blasting vibration response of a reinforced concrete building

为探讨钢筋混凝土建筑结构的爆破地震效应特性,通过在隧道爆破开挖过程中下穿的多层钢筋混凝土建筑沿高度方向上布设测点,采集了大量的钢筋混凝土建筑的爆破地震响应信号。采用小波分析和快速傅里叶变换相结合的方法,研究各方向爆破地震波作用下钢筋混凝土建筑沿高度方向的结构响应频谱、能量分布特性及幅值变化规律。研究结果表明,爆破地震波作用下钢筋混凝土结构建筑物各层质点的速度响应信号频率较大且占有较大能量比例的优势频带较宽,集中在15Hz～600Hz;钢筋混凝土结构在垂向方向的速度响应信号频率要低于水平方向,在垂直方向的速度响应峰值高于水平方向,且比值一般随着楼层的升高有增大的趋势;垂向和水平方向的信号频谱特征和峰值速度响应随楼层变化无明显变化规律可循。

To discuss characteristics of blasting vibration response of a reinforced concrete building, a large number of blasting vibration response signals of the reinforced concrete building were collected at located measuring points on the multi-story reinforced concrete building under-drilled through in the course of blasting excavation of a tunnel along the height direction. Distribution characteristics of the frequency spectrum and the energy and the amplitude variation laws of the structural response along the height direction to the blasting seismic waves in all directions were studied with the method of wavelet analysis combined with FFT. The results indicated that the frequencies of the velocity response signals of the reinforced concrete building are relatively larger and the dominant frequency bands occupying larger portions of the total energy were wider, mainly focusing in range of 15Hz -600Hz; the frequencies of the velocity response signals were in vertical direction are individually lower than those in horizontal direction, but their amplitudes are reverse; and the ratios of the latter to the former raise with the increase in the height; with the height changing, the characteristics of the frequency spectrum and the amplitude of the structural response signals in both vertical and horizontal directions versus stories vary with no obvious laws.