Shaking table test on seismic response of an accumulation landslide reinforced by pile-plate retaining wall based on the time-frequency analysis method

The time-frequency analysis method based on Hilbert-Huang transform is proposed and used to the seismic response analysis of accumulation landslide reinforced by pile-plate retaining wall. Taking the landslide along the Chengdu-Lanzhou Railway as the prototype, the shaking table test of the accumulation landslide reinforced by pile-plate retaining wall with a physical dimension similarity ratio of 1: 10 is designed and carried out. The results show that the acceleration response of the accumulation landslide shows obvious elevation effect in the process of loading different amplitude seismic waves, and the elevation effect of the landslide is the most significant under the 0.3g seismic wave. Then the elevation effect decreases with the increase of seismic wave amplitude. The dynamic earth pressure of the pile is distributed nonlinearly along the pile body, and the size and range of its envelope are directly proportional to the seismic wave amplitude. The maximum dynamic earth pressure of the pile appears at the embedded section, so attention should be paid to the reinforcement design of this part. The displacement response of pile also increases gradually with the seismic amplitude, and the coupling displacement mode changes from translation to rotation. In addition, it is feasible to use the time-frequency analysis method based on HHT transform to study the seismic stability of accumulation landslide reinforced by pile-plate retaining wall. The Hilbert energy spectrum analysis shows that the seismic energy is mainly concentrated in time domain of 2-6 s, and the corresponding frequency domain is 10-50 Hz. With the increase of input seismic amplitude, the difference of Hilbert energy between sliding bed and sliding body measurement points in time-frequency domain increases, and the difference of seismic response between them increases significantly. The damage inside the landslide can be identified by Hilbert marginal spectrum. Under the action of pile plate retaining wall, the damage at the bottom of the landslide mainly occurs on the slope, while the damage in the middle of the landslide mainly occurs inside.