Analysis of Consolidation Behavior of Vertical Drain-improved Ground According to Organic Matter Content

In this study, the effect of organic matter content in reclaimed clayey soils on the long-term consolidation behavior of ground improved with prefabricated vertical drains (PVD) was quantitatively investigated. Results from long-term consolidation tests on samples with organic matter content ranging from 0% to 30% showed that as organic matter content increased, both the compression index and secondary compression index increased substantially, whereas the coefficient of consolidation decreased. Applying the derived consolidation parameters to PVD design analysis confirmed that soils with higher organic content were more sensitive to the smear effect and PVD spacing, resulting in a nonlinear delay in the time required to reach the target degree of consolidation. In conclusion, to prevent construction delays in dredged and reclaimed soft ground, organic matter content must be incorporated as a design factor, and more conservative construction criteria should be applied.