Numerical Prediction of The Creep Settlement of The Improved Soft Soil Under Embankments.

The accurate prediction of consolidation settlement is one of the most important aspects of soft clay modeling which has always been a cause of concern for Geotechnical engineers. The objective of this study is to investigate the applicability of a few different computational tools for the prediction of consolidation settlement in soft ground. This argument can be summarized by the question of whether secondary consolidation begins after or during primary consolidation. As indicated in hypothesis A, there is no creep compression during the primary consolidation period; but the creep compression occurs only in the secondary compression starting at tEOP (time of primary consolidation). According to hypothesis B, the creep occurs throughout the primary consolidation period. A creep constitutive model namely Soft Soil Creep (Plaxis 3D) which uses hypothesis B, and a semi-analytical software (Settle 3D) which uses hypothesis A were employed to study the behavior of soft soil under embankments with the same parameters. Two case studies are used in the analysis, the first case is NHP Levee which was constructed in California. The second case is the I-95 Boston embankment which was constructed in 1965 over a deep layer of Boston Blue Clay. For each case, a comparison has been made between hypothesis A and B results with field data. The results show that the soil creeps before completing primary consolidation. Hence, hypothesis B is more accurate for evaluating the total consolidation settlements.