The settlement analysis for a proposed structure indicates that 6cm of settlement will occur in 4 yr and that the ultimate total settlement will be about 25cm. the analysis is based on the assumption that the compressible clay layer is drained at both its top and bottom surfaces. However it is suspected that there may not be drainage at the bottom surface. For the case of single drainage,
Estimate (a) the ultimate total settlement and (b) the time required for 6cm of settlement.