Numerical modelling of swelling/shrinkage behaviour of unsaturated soils for buried pipe stress analysis

The behavior of unsaturated, surficial soil layer of the earth is more complex than saturated sublayers. Depending on the mineralogy, some soils show significant volume changes (swell and shrink) with varying moisture contents, which is known as soil reactivity. Since most of the sub structures such as pipes, shallow foundations and basements etc. are buried in this surficial soil layer, consideration of these complex behaviors is essential for sustainable designs of structures. Since computer based Finite Element Analyses (FEA) is the most common analysing tool in many engineering design problems, it is interesting to investigate the applicability of common commercial FEA software packages to address these complex situations. This paper presents an analysis of moisture governed swell/shrink behavior of unsaturated soils as an application in pipe stress analysis to quantify stresses coming to pipes from reactive soil movements.