CVLE $351$ SOIL MECHANICS Spring $2023-2024$

Mid$-$term Exam $90$min

Name. A$.$mar. Hassan $q,$

$q,$ St$.$ No $22120185q,$

$($a$)$ Explain the concept of consolidation using spring analogy of Terzaghi. $(5\%)$

$($b$)$ What does it mean for clays to be normally consolidated $($NC$)$ or over$-$consolidated $($OC$)?$ Explain preconsolidation pressure $({}_c^{\text{'}})(10\%)$

Figure $1$ gives the plot of void ratio versus pressure data from a consolidation test.

$($a$)$ Determine the compression and swell indices, $C_c$ and $C_r.(6\%)$

$($b$)$ Determine pre$-$consolidation pressure $({}_c)(9\%)$

Figure $1.$ Plot of e versus log pressure.

Figure $2$ shows void ratio versus logarithm of time plot obtained from laboratory testing on a specimen recovered from the clay stratum in Figure $3.$

$($a$)$ Show the primary consolidation and secondary compression regions on Figure $2.(5\%)$

$($b$)$ Determine the coefficient of consolidation $(c_v)($Given: Initial height of specimen, $H_0=15mm,$ and is double drained$)(10\%)$

$($c$)$ Determine the laboratory value of $t_{100}$ from the curve and predict $t_{100}$ in the field. $(5\%)$

$($d$)$ Determine the void ratio at the end of primary consolidation $(e_p).(5\%)$