The negative skin friction on a pile develops when

$($a$)$ the soil in which $11$ is driven is sandy soil.

$($b$)$ the soil surrounding it settles more than the pile.

$($c$)$ the ground water table rises.

$($d$)$ the soil near the tip is clay.

e$)$ none of them

Cast$-$in$-$place piles $($or bored piles$)$ literally cause no displacement and ars known as

A$.$ Displacement piles

B$.$ Non displacement piles

C$.$ Compaction piles

D$.$ Both a and $b$

E$.$ not above

In piles in sand $,$Depending on their spacing within the group, the piles may ast in ons of two ways:

a$)$As block and as individual piles

b$)$ as block only

c$)$ as individual only

d$)$ batters pile and angle pile