Q$.2.$

A rectangular footing $1x1\mathrm{.}5m$ carries an applied pressure of $225kN.$ The soil at the site is shown in Figure $1.$ The depth of the groundwater table is $2\mathrm{.}5m$ below the ground surface. The depth of the footings is $D=(1+\frac{x}{10})m$ below the ground surface as shown as shown $($where $x$ is your group number$).$ The thickness of the clay layer is $(4\mathrm{.}2-\frac{x}{5})m($where $x$ is your group number$)$ as shown in Figure $1$ below. For stress increment, use $2$:$1$ method to find the stress increment. $(2$:$1$ means $2$ vertical : $1$ horizontal$).$

$($a$)$ Compute the consolidation settlement of the clay layer due to the loading from the footing. $($Treat the clay layer as $1$ layer$).$

$($b$)$ Repeat $($a$)$ if the thickness of the sand is $4m$ above the GWT instead of $2\mathrm{.}5m($everything else is the same$).$ See Figure $2.$

$($c$)$ Comment on your results on $($a$)$ and $($b$).$

Sand

Figure $1.$

Sand $=16k\frac{N}{m^3}$;${}_{st}=17k\frac{N}{m^3}$

Sand

Figure $2.$