The method described in the paper titled “Prediction of heave from the plasticity index and
percentage clay fraction of soils” by Van der Merwe (1964) has been in common use since then.
It predicts the potential heave due to the moisture change from a relatively dry state to a nearsaturated
state under a covered area, i.e. a maximum state change. In reality this may not always
be the case, and this Note proposes an adaptation to the method whereby the probable change
in moisture content is utilised in the calculation. This is determined by the in-situ moisture and
the estimated equilibrium moisture content (EMC) derived from the liquid limit.