应力波在层状节理岩体中的透反射与衰减规律

Transmission and Reflection and the Attenuation Law of Stress Wave in Layered Joint Rock Mass

为了研究应力波在穿越层状节理岩体发生透射和反射作用后能量的衰减规律,基于Froude相似比例法制作了层状节理岩体模型,并对模型进行瞬时冲击实验研究。通过对不同位置的加速度时程信号的分析,得出应力波因在节理结构面之间的透反射波的叠加作用形成增强信号,使得穿过节理后的时程信号峰值均未在刚起跳时达到最大,而是起跳后的一段时间先后出现峰值。通过离散快速傅里叶变换对时域信号进行频谱特性分析,得出规律:节理对应力波的阻隔作用使节理前后信号的主频和频率内最大振幅均呈非线性降低趋势,信号的高频部分迅速衰减、能量逐渐被吸收。

In order to research the attenuation law of energy in the process that stress wave crosses the rock mass with layered joint forms transmission and reflection.The model of the rock mass with layered joint was made according to the Froude proportion method,and then the instantaneous impact experiment was conducted on the model.Based on the analysis of the time-domain signal of the acceleration in different locations,it shows that the peaks of time-history signals which passed the joint are maximum during the time after its jumping instead of at the beginning of its jumping because the enhanced signals formed due to the superposition effect of the transmission and reflection wave which formed between each two of the layers.According to the analysis of the frequency spectrum characteristic of the time-domain signal with the discrete fast Fourier transformation,the results show that the dominant frequency and the maximum amplitude of the signals before and after the joint decrease in a nonlinear way,the high frequency part of signal attenuate rapidly,energy is absorbed gradually which are caused by blocking effect of the joint on the stress wave.