Q$1$: A column is supported by piles with a diameter of $400mm$ and a length of $10m$ in a clay deposit $($qu$=150K\frac{N}{m}2).$ The piles are separated by $600$ millimeters. There are $12$ piles, which are arranged in a square pattem. Calculate $($a$)$ the ultimate pile load capacity of the group, $($b$)$ its efficiency, and $($c$)$ modify the group's pattern to a triangle and determine the group's efficiency under the modified pattern. Assume that the adhesion factor is equal to $0\mathrm{.}8.?$

$[25]$