Long-term settlement behavior of soft grounds and secondary compression

Settlement-time behaviors in the last stage of consolidation are studied both in the laboratory and in the field. It is shown that the long-term settlement-time curves observed in the field are linear with the logarithm of time and the rate of the long-term settlement are analogous to the rate of secondary compression measured in a laboratory. The finite difference consolidation analyses for cohesive soils exhibiting large amounts of secondary compression during primary consolidation provide fairly good predictions of the settlement-time curves observed in the laboratory and in the field. In this paper, the applicability of the secondary compression model established in the laboratory is examined in in situ conditions. The initial rate of secondary compression used in this paper has a predominant influence on the settlement-time curve with different drainage distances. It is emphasized that the assumption for unknown secondary compression behaviors during the primary consolidation has a predominant influence on the settlement-time curve.