At the site described in Problem $6\mathrm{.}5,$ the hydraulic fill is underlain by a $15$ m thick deposit of

medium stiff, normally consolidated silty clay with the following properties:

Water content $=40\%$

Liquid limit $=46$

Plastic limit $=23$

Saturated unit weight $=15\mathrm{.}9$ kN$/$m$3$

Cone tip resistance $=8$ to $14$ kg$/$crrr$\text{'}$

Undrained shear strength $=27$ to $61$ kPa

$($a$)$ Estimate the shear wave velocity of the silty clay at a depth of $20$ m by as many procedures

as the available data will support.

$($b$)$ Shear wave velocity measurements at this site have indicated silty clay shear wave veloc$-$

ities ranging from about $120$ m$/$sec $-180$ m$/$sec at $20$ m depth with an average value of

about $155$ m$/$sec$.$ Comment on the level of agreement between the estimated shear wave

velocities from Part $($a$)$ and the measured shear wave vel