Why are sleeves often installed inside the lower part of open-ended driven piles?

In marine piles, open-ended piles are more often used than close-ended piles to enhance longer length of piles installed. This is essential to provide better lateral resistance against berthing loads and other lateral loads in marine structures.

To enhance longer length of driven piles installed, sleeves can be employed inside the lower part of open-ended driven piles. The sleeves lead to improved drivability with more soil entering the pile to from soil plug. The longer is the sleeves, the higher is the plugged length. This is because there is higher stress release experienced by soils flowing past the sleeves.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.