*4.2. Comparison with Precedent Studies*

The representative constitutive relationship equations were compared to previous studies that had similar basic physical properties such as a classification of soil and Atterberg limits. The constitutive equations proposed in this paper and those presented by Carrier et al. [10] were plotted, as shown in Figure 16. The relationships of void ratio–effective stress were plotted in the low effective stress range at the same void ratio. The equations were similar to Horton, Naumee River, Todedo and Craney Island clays, which had similar physical properties. The permeability of Korean clay had a comparatively high range at the same void ratio. The constitutive relationship equations were similarly analyzed for aluminum red mud (LL = 41–46%, PI = 7–9), FGD (Flue-Gas Desulfurization) sludge (LL = 65%, PI = 17), and Craney Island clay.

**Figure 16.** Comparison of our study and the study by Carrier et al. [10]: (**a**) void ratio vs. effective stress; (**b**) void ratio vs. permeability.

Yamagami et al. [15] proposed the power function relationship equations of void ratio–effective stress and void ratio–permeability coefficient for each stage of settling and consolidation during the estimation of settling and consolidation characteristics from back analysis. The equations proposed here were plotted and compared with the constitutive equations for mud A (PI = 40.1) and mud B (PI = 22.5) presented by Yamagami et al., as shown in Figure 17. The equation for mud A was similar to that of the e-σ'-k of bs-L-clay and gy-L-clay; mud B showed low compressibility and high permeability at high void ratio ranges. The representative constitutive equations in this study were compared to the existing research data that had similar physical properties as a Korean marine soft soil, and the results showed a similar range.

**Figure 17.** Comparison of our study and the study by Yamagami et al. [15]: (**a**) void ratio vs. effective stress; (**b**) void ratio vs. permeability.
