Model Study on Arching Above Buried Structures

The authors establish an analytical structural model of arching above an underground structure. The model was based on various experimental parameters, permitted analysis of the behavior of the soil-structure system and provided design criteria for buried structures. Owing to relations between structure and soil rigidities, stress trajectories arise in soil in a shape of an arch that transmits forces from above the structure to the arch abutments. It is assumed that the behavior of this structural arch is governed by the soil characteristic and by the support conditions along the arch and its abutments. An experimental study carried out in a glass walled container, filled with sand, can be summarized as follows: (1) Arching increases with structure depth but tends toward a definite value; (2) arching increases with external load; the rate of this increase varies with depth; (3) arching increases with the height of protruding roofs; vanishing with increasing depth; and (4) a direct relation can be found between the arching and the sand rigidity at the arch abutments.