Q. An undisturbed soil sample was taken from the middle of a clay layer (i.e., 1.5 m below GL), as shown in figure. The water table was at the top of clay layer. Laboratory test result are as follows:
Natural water content of clay : 25%
Preconsolidation pressure of clay : 60 kPa
Compression index of clay : 0.50
Recompression index of clay : 0.05
Specific gravity of clay : 2.70
Bulk unit weight of sand :
17kN/m3
A compacted fill of 2.5 m height with unit weight of
20kN/m3 is placed at the ground level.
![](https://df0b18phdhzpx.cloudfront.net/ckeditor_assets/pictures/1193384/original_29.png)
Assuming unit weight of water as
10kN/m3, the ultimate consolidation settlement (expressed in mm) of the clay layer is .