$.$ SPT problem in sand:

A standard penetration test has been conducted on a coarse sand at a depth of $16$ ft below the ground

surface. The blow counts obtained were as follows:

$0-6$ inch $4$ blows

$6-12$ inch $6$ blows

$12-18$ inch $6$ blows

The tests were conducted using a USA$-$style donut hammer in a $6-$in diameter boring using a standard

sampler with the liner installed. The vertical effective stress at the test depth was $1500$ psf$.$

$($a$)$ Determine N$60$

$($b$)$ Estimate $($N$1)60$ and comment on the effect of the various overburden correction equations on it$.$

$($c$)$ Estimate the friction angle, $\backslash$Phi $$ using your answers for $($a$)$ and $($b$).$ Comment on the results.

$($d$)$ Estimate the relative density, Dr

$($e$)$ How dense$/$loose is the sand?