Dynamic Response of Parallel Overlapped Tunnel under Seismic Loading by Shaking Table Tests

Figure 13

Decomposed wavelet packet frequency band number and frequency range. Note. S is the original input signal, A is an approximate signal, and D is the detailed signal (relatively high frequency). The width of each frequency band is 50/8 = 6.23 Hz, and the corresponding lowest frequency band is 02∼0.6 Hz.