**1. Introduction**

The demand for land is addressed efficiently through the reclamation of foreshores, which include vast lands for industrial use, dwellings, airports, and harbors. Superior soil, suitable for making grounds through the reclamation of the foreshore, has been depleted due to resource exhaustion and environmental preservation, and marine soft soil is used to substitute soil to be reclaimed from nearby sites. Each year, over 30 million m<sup>3</sup> of dredged soil is used for the environmental reformation of offshores and estuaries, harbor construction, and maintenance of waterways. Recently, dredged soil has been reclaimed to dumping areas only because the 1996 Protocol to the London Convention has not permitted ocean dumping from January 2009. The dredged marine soft soil is reclaimed to dump areas due to demands for new ground and the treatment of a huge amount of dredged soil.

In Korea, most of the dredged marine soft soil is reclaimed due to its high water content; however, the difference between construction methods as well as the very weak strength and large settlement of the soft soil is a problem. Settlement is the main geotechnical issue related to the stability and estimation of the amount of dredged soil.

The difference between actual settlement and Terzaghi's one-dimensional consolidation theory is well explained by Gibson et al. [1] and Cargill [2]. Finite strain consolidation theory induces a large strain consolidation phenomenon without numerical inconsistency and, specifically, it applies nonlinear compressibility and permeability. Numerical analysis conducted using the equation that is governed by the finite strain consolidation theory is known to estimate a large consolidation settlement [3–7]. Finite strain consolidation theory is not commonly applied to the design and construction in Korea. The general reasons are the lack of understanding of the theory, and difficulty in estimating input data and analyzing the numerical input or result.

The studies on void ratio-effective stress and void ratio-permeability have mainly focused on the exponential or power equation. Somogyi [8,9] proposed a constitution equation as a power law. Carrier et al. [10] proposed a constitution equation of modified power laws by analyzing the relationship between physical character (Atterberg limits and Activity) and the coefficient of the constitution equation. Gibson et al. [11] proposed an exponential constitution equation to simplify the consolidation governing equation.

Non-linear relationships between void ratio and effective stress, and void ratio and permeability, which directly affect settlement behavior, are observed in the high water content range of dredged soil. The non-linear constitution equation in a high water content range is difficult to estimate by conducting direct experiments. To overcome this problem, consolidation tests and settlement tests are carried out, and the results of these tests are back-analyzed through numerical analysis based on the finite strain consolidation theory. Therefore, in this study, representative relationship equations of void ratio-effective stress and void ratio-permeability of marine soft soil in Korea are proposed using finite strain consolidation theory.
