Given the following scenario: there is a sand layer with a thickness of $3$ m$,$ and below it$,$ there is a clay layer with a thickness of $5$ m$.$ The groundwater level coincides with the surface, the unit weight of the sand is $2\mathrm{.}0$ t$/$m$^3,$ the unit weight of the clay is $1\mathrm{.}8$ t$/$m$^3,$ the initial void ratio $0=1\mathrm{.}0$e $0=1\mathrm{.}0,$ and the compression index $=0\mathrm{.}4$C c $=0\mathrm{.}4.$ If the groundwater level drops by $3$ m due to some cause, what is the amount of consolidation settlement in the clay layer? $($Assume