Effect of surcharge width on evolution of soil arching for active and passive trapdoor

Soil arching is inevitably affected by external loading; however, the influence of surcharge width has been not fully understood. In this study, the arching effect under six surcharge widths and three different levels of surcharge in active and passive trapdoor models were comprehensively examined using discrete element simulation. The results showed that the majority of the active and passive arching effects were degraded due to the application of surcharge. For active arching, as the ratio between the width of loading plate (W) and the width of trapdoor (B) increased, the minimum soil arching ratio (ρmin) slightly increased and then decreased. Moreover, for W/B ≤ 1, ρmin increased with increasing magnitude of surcharge, whereas for W/B > 1, the influence of surcharge decreased. Furthermore, for passive arching, the maximum soil arching ratio initially decreased to a valley at W = 0.75B and then increased.