Earth Pressure Calculation of High Fill Culvert Considering Inclination of Soil Column Interface

In current theory of earth pressure calculations for high fill culverts, the extended modes of sliding surface and shear friction stress are always neglected, leading to great difference between theoretical calculations and field measurements. To overcome this drawback, a novel earth pressure theory for high fill culverts is developed, which takes into account extension modes of sliding surface and shear friction stress. Firstly, a finite element method (FEM) model of the high fill culvert is established by Plaxis2D. In addition, extension modes of sliding surface and directions of shear friction stress are summarized by FEM simulations. Secondly, based on the limit equilibrium theory of granular materials, theoretical equations of positive projecting (PP) and induced trench installation (ITI) culvert considering extension modes of sliding surface and shear friction stress are derived. Thirdly, the theoretical calculations are in good agreement with field measurements and numerical simulations, demonstrating the accuracy of the PP and ITI culvert theoretical equations. Finally, a parametric analysis is performed to explore how three main factors, including fill height, thickness of the expanded polystyrene (EPS) geofoam, and the ratio of the deformation modulus of fill to the EPS geofoam block, affected the earth pressure on the culvert top.