基于小波包的地下洞室群地震响应及其频谱特性研究

基于有限差分数值模拟,在合理选择地震动力分析阻尼参数的条件下,开展白鹤滩水电工程13#机组剖面地下洞群围岩地震响应研究,并结合小波包变换方法从加速度峰值及振动能量角度评价了地震波在岩体中的传播规律及洞室群不同区域地震响应的频谱特征。结果表明:地震波传播过程中强度随高程增加而增加,层间错动带有一定减震作用;小波包分解可以较全面地给出地震响应成分的频率分布;地震波的高频分量在岩体传播过程中逐渐衰减;在地下洞室群附近,岩体地震响应的加速度峰值和振动能量频谱特征以1～3Hz频段为主,其他频段对岩体地震响应影响较小。

Spectrum characteristics analysis of seismic response for underground caverns via wavelet packet

Based on proper damping parameters, a finite difference numerical simulation is conducted for the seismic analysis of the Baihetan underground caverns. Wavelet packet analysis is made for the evaluation of wave propagation and spectrum characteristics of seismic response from the point of view of peak acceleration and vibration energy. Results indicate that seismic intensity increases with the elevation and fault zones possess vibration-suppressing effect. Spectrum characteristics of seismic response can be clearly revealed by wavelet packet. High-frequency components of seismic wave are gradually absorbed during propagation. A major influential frequency band of peak acceleration and vibration energy spectrum characteristics is obtained as 1-3Hz for wall rock, and other bands have minor effects.