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http://dx.doi.org/10.12814/jkgss.2021.20.4.009

Assessment of Overconsolidation Ratio by Depth of Soft Ground: A Case Study in South Korea  

Lee, Jong-Young (Department of Civil and Environmental Engineering, Chung-Ang Univ.)
Han, Jung-Geun (Department of Civil&Environmental Engineering and Intelligent Energy&Industry, Chung-Ang Univ.)
Publication Information
Journal of the Korean Geosynthetics Society / v.20, no.4, 2021 , pp. 9-18 More about this Journal
Abstract
In this study, the overconsolidation ratio (OCR) of soft clay soil was calculated by conducting an indoor physical experiment and a dynamics test using undisturbed soil samples from a soft clay soil field in South Korea. The OCR by depth was predicted by comparing the experimental results with the existing empirical equations. Methods using the liquidity index and the existing empirical equation by the Naval Facilities Engineering Systems Command (NAVFAC) were examined, and the results were compared with the actual measured values. The method using the liquidity index was found to be suitable for estimating the rough OCR of the ground. However, the effect of drying was not considered for the ground above the groundwater level. Therefore, an equation for the correlation equation between the depth and OCR of each region, including the ground above the groundwater level, was proposed. The proposed equation was applied to the OCR prediction of the adjacent area. The predicted values in the area composed of clay (CL, CH) were found to be in good agreement with the actual values. In the region composed of silt (ML), however, the predicted values were not consistent with the actual values. This suggests that the sedimentation and compositional characteristics, rather than the engineering characteristics of the soil, are important factors that affect the OCR prediction.
Keywords
Overconsolidation ratio(OCR); Empirical formula; Liquid index; Soft ground;
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