Energy-based analysis of seismic damage mechanism of multi-anchor piles in tunnel crossing landslide area

To study the damage mechanism of multi-anchor piles in tunnel crossing landslide area under earthquake, the damping performance of multi-anchor piles was discussed. The energy dissipation springs were used as the optimization device of the anchor head to carry out the shaking table comparison test on the reinforced slope. The Hilbert spectrum and Hilbert marginal spectrum were proposed to analyze the seismic damage mechanism of the multi-anchor piles, and the peak Fourier spectrum amplitude (PFSA) was used to verify the effectiveness of the method. The results show that the seismic energy is concentrated in the high-frequency component (30–40 Hz) of the Hilbert spectrum and the low-frequency component (12–30 Hz) of the marginal spectrum. This indicates that they can be combined with the distribution law of the PFSA to identify the overall and local dynamic responses of the multi-anchored piles, respectively. The stretchable deformation of the energy-dissipation springs improves the coordination of the multi-anchor piles, resulting in better pile integrity. The damage mechanism of the multi-anchor piles is elucidated based on the energy method: local damage at the top and middle areas of the multi-anchor piles is mainly caused by the low-frequency component (12–30 Hz) of the marginal spectrum under the action of 0.15g and 0.20g seismic intensities. As the seismic intensity increases to 0.30g, the dynamic response of the slope is further amplified by the high-frequency component (30–40 Hz) of the Hilbert energy spectrum, which leads to the overall damage of the multi-anchor piles.