**5. Conclusions**

In this study, the marine soft soil that was sampled at dredging and reclamation sites in Korea was analyzed, and the representative constitutive relationship equations were proposed as follows:

The consolidation property was classified according to LL = 60% for Busan and Gwangyang marine clay and according to LL = 30% for Incheon marine clay by conducting basic physical property tests and consolidation tests for 23 marine soft soils in the Busan, Gwangyang, and Incheon regions. Busan clay showed a slightly higher consolidation settlement property than Gwangyang clay. Incheon clay showed the lowest consolidation settlement property among the three regions. The void ratio–effective stress and void ratio–permeability coefficient were estimated using the back analysis and centrifugal experiment with high void ratios, and the constitutive relationships were shown to be similar in terms of region and properties. This is a reasonable analysis procedure to carry out the consolidation experimental high void ratios using the centrifugal experiment, and then to estimate the constitutive relationship equation by back analysis from the result of the centrifugal experiment. Furthermore, the constitutive relationship equation for Korean clay was analyzed to be a reasonable power function equation. The representative constitutive relationship equations of each region were analyzed by estimating each constitutive equation for each specimen using the back analysis and centrifugal experiment, and then the specimens were classified on the basis of LL criteria, reflecting the engineering properties. For future study, a design chart for estimating the consolidation phenomenon of marine soft soil will be proposed using the constitutive relationship equations.

**Author Contributions:** Conceptualization, S.H.J. and H.J.K.; Methodology, S.H.J.; Investigation, S.H.J.; Writing—original draft preparation, S.H.J.; Writing—review and editing, H.J.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflicts of interest.
