This paper describes the mechanical properties of light-weight soil which were improved using cement and foam. Especially, failure criterion of light-weight soil, the influence of unconfined compressive strength and initial void ratio on light-weight soil is studied.
From the results of these studies, it is clear that the failure criterion should be described using q-p' relation and e-logp' relation. It was also learned that the unconfined compressive strength and initial void ratio of light-weight soil is influenced by slope failure of q-p' (M) line and e-logp' (Cc) line.