Effect of Seismic Shaking on Soil Arching Effect at Different Initial States

The impact of seismic shaking on the soil arching effect at different initial states is not clear. This study presents a comprehensive comparison of the soil arching effect under five initial states and three burial depths subjected to seismic shaking, utilizing numerical trapdoor tests performed with the discrete element method. The results showed that following the multi‐stage fluctuations caused by seismic wave input, the ultimate arching ratio increased, signaling a weakening of the soil arching effect. The difference in the soil arching ratio gradually decreased as the trapdoor displacement increased. For the same burial depth, the variation in the soil arching ratio exhibited a quadratic relationship with the normalized trapdoor displacement. As trapdoor displacement increased, the stress ratio changes oscillated in response to seismic waves, with direction inversely related to the waveforms. The areas most affected by seismic shaking were near the trapdoor. An increase in normalized trapdoor displacement corresponds to a decrease in the ultimate coordination number, which follows an inverse relationship that can be described by a linear function. After seismic action, force chains above the trapdoor strengthened, while their intensity decreased in the stable region. Increased burial depth amplified seismic‐induced force chains within the trapdoor width. The major axis orientation and shape in the contact rose diagrams remained unchanged, though horizontal contacts increased, with this increase becoming more pronounced as trapdoor displacement grew.