Evolution mechanism of active soil arching in a shallow trapdoor under eccentric loading

Abstract

This study provides insight into the effect of eccentric loading on soil arching. A numerical trapdoor model was developed using the discrete element method to investigate the evolution mechanism by considering the magnitude of the surcharge and the deviation distance. The parameters were validated using laboratory results. The numerical results showed that the Ground reaction curve (GRC) on the trapdoor could be divided into two categories. GRC type I included stages of initial soil arching, maximum soil arching, load recovery, and an ultimate stage. For GRC type II, the ultimate stage was replaced by a declining stage. The minimum soil arching ratio increased with the increasing surcharge, but decreased with the increasing deviation distance within 0.75B (B is the trapdoor width). The vertical displacement field inclined as the load deviated from the centered position, transforming from a trapezoid to a quadrilateral. The soil arching effect was degraded by the surcharge.