Centrifuge modeling of seismic response of slope on partially replaced soft soil ground

The slope on coastal soft soil ground creates a significant risk of landslide and settlement during an earthquake, causing damage to overlying structures. Soil replacement is an effective method to improve the seismic stability of coastal soft soil ground. The seismic response and stability of soft soil ground and slopes before and after replacement are investigated by centrifuge shaking table tests. Results show that the acceleration response of the backfill slope increases after the soft soil is replaced. The instantaneous settlement increases while post-earthquake settlement significantly decreases. There is a significant hysteresis in the seismic pore pressure response of soft clay. The time required for the pore pressure to reach its peak value decreases after the soft soil is replaced, while the peak seismic pore pressure value decreases significantly. Replacing the soft soil foundation can improve the drainage boundary, accelerate the dissipation of seismic excess pore pressure, and greatly reduce post-earthquake settlement. When a seismic wave is applied, a slip occurs along the interface between gravel and clay; this slip range is also reduced after the soil is replaced. The results of this work indicate that soft soil ground replacement can enhance seismic stability, providing a workable reference for the treatment of coastal soft soil ground.