Oedometer tests starting from a very small effective vertical stress of 0·5 kPa were performed on three reconstituted clays with different liquid limits. The soils were prepared at various initial water contents, ranging from 0·7 to 2·0 times their corresponding liquid limits. It is observed that the e–log [ ] compression curves show an inverse ‘S' shape due to suction pressure resisting deformation, similar to that of soft natural clays caused by consolidation yield stress. The suction pressure [ ] of the reconstituted clays can be correlated with the ratio of initial void ratio to void ratio at liquid limit e₀/e_L. The suction pressure curve defined by a unique relationship between suction pressure [ ] and the normalised void ratio at suction pressure e_s/e_Lis also proposed to distinguish between the pre-suction and the post-suction states. In addition, Burland's concept of the intrinsic compression line is adopted for correlating the compression curves of various reconstituted clays at high initial water contents. It has been found that the void index is a powerful parameter for normalising the compression curves in the post-suction state. Nevertheless, it seems that Burland's intrinsic compression line slightly underestimates the void index at the low stresses considered in this study. An extended intrinsic compression line is then derived in order to better fit the data for stresses lower than 25 kPa.

Oedometer tests were carried out using modified oedometer apparatuses on three different kinds of dredged slurries. Test results show that the compressibility of dredged slurries is influenced by initial water content when the initial water content is lower than upper limit water content. When the initial water content is higher than the upper limit water content, the compressibility is irrelevant with the initial water content. Result also shows that the upper limit water content is about three times their liquid limit. The compression curves of samples at the initial water content exceeding the upper limit water content overlap to a single curve. This compression curve is named as Top Compression Line (TCL) when it locates above the other compression curves of the same soil. At last, a normalized equation is obtained to normalize TCL of different soils.