The surface stiffness of expanded clay embankments is determined by plate load testing.
The stiffness values obtainable will depend on the technical solution chosen, the grain size of the expanded clay, and the degree of compaction.
The various methods for constructing an embankments can be referred on the website. As a thumb rule these include a finishing layer to distribute the loading. An asymptotic value of Md = 200 Kg/cm2 can be considered for design purposes, which corresponds to a degree of compaction of the aggregate that is easy to attain using ordinary ground-compacting machinery (plate vibrators, compaction rollers).