Effect of particle shape on the development of 2D soil arching

This study presents the effects of the particle shape on soil arching by simulating the trapdoor problem using the discrete element method (DEM). A new method for preparing the samples with irregular particle in the DEM is proposed to obtain a similar and reasonable initial stress state. Simple monitoring of the strain field is demonstrated. The results indicate that as the trapdoor moves downward, the critical height at which the measurable differential settlement vanishes increases then remains steady. The final critical height increases with decreasing sphericity or increasing roundness, in which the sphericity is the main influencing factor. Two types of shear bands propagate from the edge of the trapdoor into the specimens. As the interlocking between the irregular particles increases, the shear strain decreases, but the dilation increases inside the shear band. The particle shape affects the development rate of soil arching, but has a limited effect on the ultimate soil arching behaviour. The rotation of the major principal directions of anisotropy and the decrease in the anisotropy intensity are microcosmic reason of soil arching. Both of the rotation and decrease mainly occur in a relatively small trapdoor displacement, restricted by the increase in the interlocking between irregular particles.