Plot the laboratory effective vertical stress vs$.$ void ratio curve on both arithmetic and

semilogarithmic graphs. Note: Don$$t connect the points with straight lines. Instead, draw a

smooth curve through the points $($this will make step $2$ easier$).$ Plots should be drawn using a

software $($e$.$g$.,$ Excel$).$ Points will be deducted for hand$-$drawn plots.

$2$b$)$ Determine the preconsolidation stress for the sample. Present your approach graphically on

your plot.

$2$c$)$ Determine the present vertical effective stress at the location of the sample.

CIVILEN $3540$

HW$8$

$2$d$)$ What is the OCR of the sample? Is the clay normally consolidated or overconsolidated?

$2$e$)$ Construct the field compression curve. Note: eo$=0\mathrm{.}4.$ Present your approach graphically on

your plot.

$2$f$)$ Calculate Cc and Cs$.$ Note: Cc from the constructed field curve, Cs from lab unloading curve.

$2$g$)$ A wide highway embankment $($unit weight $=20\mathrm{.}5$ kN$/$m$3)$ is to be constructed on the site.

Estimate the total consolidation settlement if the height of the embankment is a$)3\mathrm{.}6$m$,$ b$)35$

m$.$ For both cases, solve the problem using appropriate settlement equation $($with Cc and Cs$).$

Assume the sand is incompressible.

$2$h$)$ If on$-$site clay has a Cv value of $3$ m$2/$yr$,$ estimate the time required for $90\%$ of settlement to

occur. The bedrock is highly fractured and, hence, can be considered as a drainage boundary.