Scaled physical and numerical modelling of static soil pressures on box culverts

Abstract

The response of buried box culverts is a complex soil–structure interaction problem, where the relative stiffness between the soil and structure is a critical factor. In addition, soil arching is an important aspect of the soil–culvert interaction problem. A series of static scaled physical model centrifuge tests were performed to investigate soil–culvert interaction. Two different box culvert thicknesses and Nevada sand specimens with different relative densities were used to explore the interaction between the sand and box culverts under different conditions. The static loading consisted of the self-weight from the soil body. The responses of the box culvert were recorded for all loading conditions. The results were evaluated in terms of bending moment, soil pressure, and soil–culvert interaction factors. Soil pressures were evaluated using different experimental methods, which provided comparable results. The soil pressure observed on the culvert top slab showed parabolic distribution, i.e., higher values at the edges and lower at the centre than the theoretical vertical soil (overburden) pressure. The horizontal soil pressure on the side wall increased with depth. The soil–culvert interaction factors decreased at the centre and increased at the edges of the top slab, as the thickness and relative stiffness of the culvert decreased.