Modeling the Effects of Backfilling and Soil Compaction beside Shallow Buried Pipes

Abstract

Compaction of the soil placed beside culverts (the side-fill) can have a significant effect on the behavior of flexible and rigid structures. This is particularly true for shallow buried structures when the stresses resulting from compaction represent a greater proportion of the total stresses present. Different techniques have been reported in the literature to model soil compaction during finite-element analyses. A new semiempirical technique is proposed, which takes into consideration the increase in lateral stress and soil kneading during compaction. A simple procedure is discussed to incorporate the compaction of granular material in finite-element analysis. The new technique is used to model five different pipe products composed of different materials and dimensions, and the results are compared to measured values reported in the literature. A new factor is proposed to account for soil kneading during compaction to provide an upper limit for the pipe deformations and stresses that result during installation. The technique can be used to estimate peaking in flexible culverts and the additional crown moments and thrust that result in rigid culverts.