Abstract
Purpose of this study is to propose a unified treatment of the smear effect on a delay of consolidation subjected to a clay layer improved by sand drain (SD) or pre-fabricated band shaped drain (PBD). Therefore, the finite differential method was applied to analysis this problem. As the results, it was found that the trend of delay of consolidation was taken account by the reduction ratio of hydraulic conductivity of clay. This ratio is constituted of the parameter revealing the spacing, thickness of the smear zone, radius of drain, and reduction ratio of hydraulic conductivity. In this paper, the relationship between spacing of drain, delay of consolidation, and smear effect depending on the methodologies of vertical drains is arranged on the same figure and is shown to scatter in the narrow zone.
