PROBLEM $2.(20$ POINTS$)$

The average SPT $N_{60}$ value for a sand stratum was $25$ taken from $3\mathrm{.}5m$ depth. The GWT is $2m$ below the surface. The total unit weight of soil above GWT is $18\mathrm{.}6k\frac{N}{m^3}.$ A $2\mathrm{.}5mx2\mathrm{.}5m$ footing is to be placed at a depth of $3\mathrm{.}5m$ below the ground surface. Determine:

A$.(10$ points$)$ The allowable bearing capacity

B$.(10$ points$)$ The vertical load the footing can support safely for a maximum of $1\mathrm{.}5cm$ settlement.

HINT: Need to make a plausible determination of saturated unit weight of sand.