Used DeWaal pile as a lower cost alternate to driven steel H-pile on a job about 4 years ago (several hundred piles for a cooling tower foundation). They have been entirely satifactory and I would accept them again.
They are a proprietary product in the USA so would be careful about specifying them in a competitive bid situation.
Here is a link to a descriiption by the contractor (very reputable) who has the US rights to use them:
The De Waal pile is one of the many types of drilled cast in-situ displacement piles. In the States Berkel has developed its own displacement pile. Other types are the Omega pile, the Atlas pile, for the most famous.
Morris Shea just completed a large job here in Atlanta. An old steel plant was replaced with a mixed use community. They did not want to use auger cast as the contaminated spoil would have to be disposed of. Such a pile also develops a larger load as the soil is compressed near it.
Engineering is the art of not constructing...of doing that well with one dollar what any bungler can do well with two after a fashion.
Here it is common practice to install De Waal-piles (or in fact all types of screw piles with ground displacement). IMHO this is a very good method for installing piles. Not to expensive and technically very good if installed by a good pile installer. We mainly use this type of pile, in any kind of soil.
If you want some info about installing this type of pile (screw injection pile (vibration free, displacement pile)), go to
