Effects of fill material on load of concrete box culvert installed in trench – numerical analysis

The supporting mechanism for a concrete box culvert installed in a trench is different from that for an embankment-installed culvert, but limited research has been carried out regarding the effects of fill parameters and type on the performance of this culvert. A parametric study using the plastic-hardening model for the fill material indicates that the soil–structure interaction (SSI) factor for the culvert’s top slab decreased with the fill’s Poisson’s ratio and stiffness. In addition, the SSI factor for the culvert’s bottom slab increased with the fill cohesion and friction angle but decreased with the fill’s Poisson’s ratio and stiffness. Furthermore, a more compacted fill resulted in a smaller SSI factor for the culvert’s top slab than the less-compacted fill. However, a more compacted fill may not result in a smaller SSI factor for the culvert’s bottom slab than the less compacted fill.