Mechanics of arch action in soil arching

Soil arching is relevant in various engineering applications such as tunnels, underground pipelines, and culverts, where there is a relative movement between soil and structure. Rigorous efforts in the past few decades paved the way in implementing trapdoor experiments to study this exciting phenomenon of soil arching. The evolution of failure planes with trapdoor displacement and the arch's orientations, and other morphological characteristics are discussed in this study. This research points to the existence of a soil arch having a cubic polynomial profile in the yielding zone over the trapdoor. The observed reoriented major and minor principal stresses in the tangential and radial direction justify the compressive nature of the arch. Mohr's circle representations are used to define the orientations of principal stresses and their magnitudes along the arch. An expression is derived to predict the post-arching load (residual load) on the trapdoor, and extensive comparison with the existing predictions has been undertaken. The present study, validated using numerical and centrifuge model tests (from literature), confirms its suitability in real-world situations and highlights the possibilities of practical implementations of the research outcomes, especially in the design aspects.