Abstract: By simulating the “trapdoor” test of Terzaghi using discrete element program, the characteristics of displacement of particles and load transfer are studied from granular and microcosmic viewpoint when soil arching existing in frictional geotechnical material; moreover, the influences of particle diameter, porosity, particle frictional coefficient, width of trapdoor and trapdoor displacement on soil arching are also studied. The results indicate that due to the effect of soil arching, the vertical loading above soil arching is transformed to horizontal loading within a certain range above the arch foot; then the horizontal loading will transfer to both sides of soil, which leads to horizontal displacement of soil. When the trapdoor moves downward, the effect of soil arching evolves continuously; and enlarging the particle diameter and frictional coefficient, decreasing porosity and trapdoor width will not only enhance the effect of soil arching but also narrow the influence range of soil arching.

Key words: soil arching, frictional geotechnical material, microcosmic mechanism, discrete elements