Question $2$

The blow counts for an SPTtest at a depth of $5m(15ft)$ in a coarse$-$grained soil at

every $152$ m $(6$ in $.)$ are $8,12,15.$ A donut hammer with $ER=45\%$ and a standard

sampler were used in a borehole $152$ mm $(6$ in $.)$ diameter.

$($l$)$ Determine the N value. $(2)$ Correct the N value for rod length, sampler type,

borehole size, and energy ratio of $60\%.$

$(3)$ Make a preliminary description of the compactness of the soil. The rod length

measured from the depth of the test to the anvil is $6m(20ft).$

Groundwater level is $m(30ft)$ below the surface.