Numerical Modelling of Induced Stresses in Buried Corrugated Metal Structures due to Compaction Efforts

Abstract

An essential element of composite soil-structure pipe and/or culvert systems is the backfilling process, where compaction efforts are applied to newly placed soil layers surrounding flexible corrugated metal pipes/culverts (CMPs/CMCs). Compaction of the layers of the side backfill has a significant effect on the culvert wall response, based on the relative stiffness of the buried structure and the backfill soil material. In the literature, various compaction modelling procedures are described which compute lateral stresses induced in flexible buried culverts due to the backfill compaction. However, a disadvantage of many of these procedures is the simulation of the soil material as an elastic medium, since this results in rebound behavior following removal of the compaction loads. This paper investigates several procedures for applying compaction efforts in two-dimensional finite element analyses (FEA). New numerical modelling procedures are proposed to simulate the effect of soil compaction on buried culverts, including modifications to existing modelling procedures to improve their ability to capture the culvert response. The numerical modelling results are compared with the results of three full-scale tests of buried corrugated metal structures. These structures include an arch pipe and an open-bottom arch culvert in Sweden and a horizontal ellipse pipe in Canada. Based on the analyses, this study concludes that the most effective methods for applying compaction are the use of a vertical surface loading procedure or a prescribed vertical displacement procedure. These procedures provide the best fit with the deformation and the bending moment measurements recorded in the field.