Question $3(20$ points$)$

Based on Figure Q$3,$ determine the following

$($i$)$ The net water pressure acting $2$ m below the excavated level on the sheet pile wall.

$($ii$)$ The maximum exit hydraulic gradient

$($iii$)$ The factor of safety against piping

$($iv$)$ Describe how piping failure could occur in the situation illustrated in Figure Q$3$ and how it can be prevented

ANS: $33$ kPa; $0.$; $1\mathrm{.}8$; see notes