Seismic response and failure mode of a shallow overburden slope reinforced with an ecological frame beam structure

Abstract

The technique of integrating vegetation and geotechnical measure is an effective and ecological method for preventing and controlling shallow landslide. A new type of ecological frame beam, a bamboo frame structure incorporating the dynamic shear resistance of plant roots (Amorpha fruticosa), was designed to reinforce shallow overburden slope. To investigate the seismic response and failure mode of the slope reinforced by this support structure, a large-scale shaking table test was conducted taking into consideration different seismic wave types and excitation amplitudes. The results show that the distribution and amplitude of low-frequency seismic components (<18 Hz) significantly influence slope displacement responses. The sudden change of natural frequency and damping ratio can also reflect the damage degree and deformation stage of the slope. Seismic damage of the slope mainly occurs at the slope shoulder and the slope crest, as well as at the left and right boundaries of the upper part of the shallow overburden. The failure mode is the continuous collapse and sliding of the shallow overburden along the stable surface, which is characterized by the crushing spreading of overburden soil mass. The ecological frame beam structure exhibits effective seismic resistance at peak seismic excitation ≤0.6 g. It is recommended to consider 2.1–3.6 times the elevation amplification effect in the seismic design of ecological frame beam structure. The root system contributes to seismic performance by reducing near-surface dynamic responses and enhancing energy dissipation capacity.