A Comparison of Approaches for Determining the Virgin Compression Line of Remolded Saturated Soils

Many advanced soil constitutive models are modifications of the Modified Cam-Clay model. They are based on the concept of critical state theory and use several parameters to simulate the mechanical behavior of soils. Among these, parameters describing the compression behavior of the soil must be determined, even though one-dimensional consolidation tests may not be available, especially for preliminary studies. This information may also be needed to switch from a less complex soil model (e.g., Mohr-Coulomb) to a more complex one (e.g., Modified Cam-Clay). In this paper, the slope of the virgin compression line (λ) was estimated by advancing the existing methods in the literature with rapid laboratory testing equipment, such as the fall cone and miniature vane shear tests. By using this approach, two methods are proposed to estimate the value of λ. Then, these methods were applied on three different soils, and the results were compared and verified using one-dimensional consolidation test. The results obtained from the proposed test methods showed an accurate estimation of the λ parameter for clays, which makes these methods reliable, fast, and economical. But, as the clay fraction of the soil decreases, the methods tend to overestimate the λ values.