Numerical Investigation of Soil Arching in Dense Sand

Soil arching is relevant in various engineering applications particularly in cases where there is relative movement between soil and structure. When a portion of the soil mass yields, redistribution of stresses take place between the yielding mass and its surrounding. Several trapdoor experiments have been performed with different improvements and extensions over the past few decades to study soil arching. Numerical modeling of a trapdoor mechanism is performed in this study and the suitability of Hardening Soil constitutive model over the Mohr-Coulomb model has been studied. In the present study, extensive parametric studies were conducted to examine the extent of the zone of influence and zone of yielding. The zone of influence, beyond which there is no influence of soil arching, is bounded by straight lines to form a trapezoidal shape. The dimensions of the influence zone depend on the fill height (H) and trapdoor width (B). The two families of failure surfaces, internal and external, are described and their categorization with respect to the H/B ratio is well explained. Furthermore, the zone of yielding and the region enclosed within limits of influence and failure planes are classified as active and passive zones, considering the dilation and compression in the direction of trapdoor displacement. The equilibrium of stress transfer in soil arching that remained as an unjustified assumption until now is systematically brought out in the present study. The present study also highlights salient characteristics of the plane of equivalent settlement and critical height. The present study throws some light on the need for further understanding of arching in various field applications, such as piled embankments, tunnels, culverts, buried pipelines, excavations supported by contiguous pile walls, and slopes stabilized by a row of piles.