Question $3$

$[5]$

Determine the critical hydraulic gradient that will cause boiling or quick condition for a sandy soil. The sand has the following properties:

Dry unit weight $,=16\mathrm{.}55k\frac{N}{m^3}$

Specific gravity $(G_s)=2\mathrm{.}72$

Voids ratio $(e),=0\mathrm{.}76$

Porosity $(n),=0\mathrm{.}43$

Question $4$

$[18]$

A sandy gravel fill $($embankment$)$ with a unit weight of $16\mathrm{.}5k\frac{N}{m^3}$ is placed on the ground as shown in figure $3$ below.

Figure $3$

The fill is placed over a $3\mathrm{.}2m$ thick layer of saturated clay with a unit weight of $16\mathrm{.}9k\frac{N}{m^3}$ and saturated unit weight of $17\mathrm{.}8k\frac{N}{m^3},$ the saturated clay is underlain by a $2\mathrm{.}8m$ thick

$3$