Culvert-soil Interaction and Load Reduction Effect of Box Culvert Installed in Trench Terrain

Abstract

Abstract Culvert-soil interaction and soil arch effect in fill are extremely complicated for box culvert installed in trench terrain. This paper conducted numerous model tests to investigate the load transfer law, earth pressure distribution and variation law of culvert-soil system under different slope angles and trench width for box culverts with/without expandable polystyrene (EPS) board load-reduction, as well as soil arch effect and its change characteristics. Research results indicate that, with EPS board load-reduction, the vertical earth pressure on the culvert top reduces obviously, while the vertical earth pressure at both sides of the culvert increase. The soil arch effect occurs in trench terrain, which transfers the vertical earth pressure from the culvert top to the slope, and its strength is closely related to the backfill height, the trench width and the slope angle. When the trench width is approximately 2 times the width of the culvert and the slope angle is 60°, the EPS load-reduction material will destroy the original soil arch, the load reduction effect is ineffective, the EPS load-reduction measures have minimal impact on the vertical earth pressure at the middle height of the side wall in trench terrain, which significantly different from the embankment installation culvert.