Question $5(16$ MARKS$)$:

The coefficient of consolidation of a clayey soil for a given pressure range from one dimensional

consolidation test results was $3{10}^{-2}m\frac{m^2}{sec}$ for the pressure range shown in Table $1.$ The clay

sample which was sandwiched between sand layers was obtained from the field Details of the soil

layer thickness and other required properties are shown in Figure $3$a$.$

a$.$ Calculate the average effective stress on the clay layer.

b$.$ Determine the compression index, $C_c.$

c$.$ Determine the total consolidation settlement under the load, ${}^{\text{'}}=100k\frac{N}{m^2}.$

d$.$ During construction, the loading of ${}^{\text{'}}$ given in part $c$ was gradual; the resulting surcharge can

be approximated as shown in Figure $3$b$.$ Estimate the settlement at $t=50$ and $t=250$ days after

the beginning of construction.

Table $1.$

$($a$)$

Figure $5$