Problem $5.$

Using Figure in the previous problem, but this time increase thickness of the proposed fill to $30$ ft $,$ the thickness of the clay to $20$ ft and replace the impervious bedrock with a Silty sand layer $($i$.$e$.$ a layer that will provide drainage$).$ Determine:

a$)$ the ultimate settlement $[S_{\text{w}\text{i}\text{t}}]$ of the clay layer $($using $1$ sub$-$layer, $[$i$.$e$.$ the entire $20ft).$

b$)$ how long it will take to get to an average degree of consolidation $U_{av}$ of $98\%,$ and what the Settlement will be at that time.

c$)$ Also, the owner of the property would like to begin construction on the property and she believes that the construction can tolerate settlement of up to $5$ inches. She would like to know how long after the fill is placed she can begin construction to limit primary settlement to $5$ inches $($i$.$e$.$ the fill is placed, consolidation begins, then you wait to build until there will only be $5^{?}$ of settlement after the building is built. Neglect the weight of the building$).$ Determine the time at which time this will occur, and the average degree of consolidation at this time.

d$)$ Also, pretend that it is possible to reach $100\%$ consolidation $($it is in reality, but not in theory$).$ At $100\%$ consolidation what is the pore water pressure $[$ u