Seismic Optimization of High Cantilever Multianchor Pile Strengthening Soil Slopes against Earthquakes

Abstract

To explore the optimal seismic performance of multianchor pile, we carried out a series of shaking table tests. Based on the special form of multianchor piles’ reinforcement, we put forward the optimal design scheme of using EPS foam as damping layers and energy-dissipation springs for improving the self-coordinating devices of anchor head. By measuring acceleration and dynamic soil-pressure response under different intensities of vibration, we analyzed the correlation between acceleration caused by seismic wave action and damage characterized by time-domain and spectral characteristics of dynamic soil-pressure. We discuss in detail the relationship between frequency and specific period of dynamic soil-pressure and acceleration. We then used the SPECTR program to calculate the energy spectrum. Under the reciprocating action of seismic waves of different intensities, our slope model showed the continuous effect of spatial coupling deformation leading to regional damage and failure. Furthermore, the spatial distribution for amplitude of acceleration and dynamic soil-pressure showed the outstanding response of lateral amplitude of pile structures without optimization. The energy-spectrum distribution of acceleration seismic input was orderly, while the dynamic soil-pressure distribution of piles was disordered. Low-frequency (≤10 Hz) seismic waves have a great influence on these structures. The difference of acceleration hysteresis along the elevations was mainly caused by the propagation stage after the main earthquake. The correlation between dynamic soil-pressure and acceleration response in each group before the pile occurred in the same earthquake area was very weak, showing a low correlation. The optimization effect of optimized structures is related to the position of the shock-absorbing layer. Under high acceleration, multianchor piles easily cause bulge failures or shear failures at the positions of sliding surfaces. These results are helpful for improvements to reliably optimize designs in pile structure dynamic parameters.