Deviatoric behaviour of compacted unsaturated soils within (q, vw, p) space—an experimental study

AbstractThe coexistence of air and water as a mixture in void spaces in unsaturated soils, makes its mechanical behaviour relatively complex and difficult to be addressed by classical saturated soil mechanics principles. In addition, many engineering problems encountered in practical situations had some part to deal with unsaturated soils and therefore the clear understanding of various behavioural patterns of unsaturated soils is crucial. To date, a large number of attempts are reported in evaluating the mechanical behaviour of unsaturated soils in different stress spaces. The present study evaluates the deviatoric behaviour of compacted unsaturated soils in deviator stress–specific water volume–mean net stress ($$q, {v}_{\mathrm{w}}, p$$ q , v w , p ) space. The effect of moisture content, confinement and the stress history on the behaviour of compacted unsaturated kaolin subjected to triaxial compression was assessed and the results showed that there exists a critical state surface for compacted unsaturated soils in $$q- {v}_{\mathrm{w}}- p$$ q - v w - p space.