A tangent or secant pile wall as sheeting for your construction pit

Pile walls for construction pit sheeting are created by making primary and secondary concrete piles, which are either secant (overlapping) or tangent (abutting) or drilled. Sometimes, the piles form an underground earth-retaining wall. In the case of a secant pile wall, it is also water-inhibiting. As a member of ABEF (the Belgian Association of Foundation Contractors), CVR participated in meetings of the ‘sheeting’ working group of the BBRI. This working group forms the basis of the implementation sheet ‘secant pile walls’.

In 1994, CVR was the pioneer in Belgium for the realisation of secant pile walls with a small pile diameter (43 centimetres). We now bore secant pile walls up to twenty metres deep with diameters of 43, 53 or 63 centimetres. A possible alternative for the traditional concrete secant pile wall is the self-developed CVR C-Mix® pile wall.

How is a secant pile wall made?

We drill a secant pile wall in different phases. There are primary and secondary piles. The primary piles are installed first. The secondary piles overlap the primary piles. The reinforcement comes in between the secondary piles.

  1. For drilling the secant pile wall, we provide a concrete guide beam which guides the casing.
  2. The drilling machines have a double drill bit. The drilled soil is transported upwards via a screw and subsequently ejected. This means that the soil around the borehole is not displaced and there is no stress relief. As there is no settlement, it is possible to drill tightly against existing foundations, without the risk of damaging the adjacent structure.
  3. After the required depth has been reached, we pump concrete through the centre of the hollow screw.
  4. We withdraw the casing to the surface while concreting, thus forming a concrete pile.
  5. If necessary, we install reinforcement in the pile wall afterwards.

What are the benefits of a secant pile wall?

  • A secant pile wall can be given a bearing function and a definitive earth-retaining function.
  • Thanks to their great rigidity, pile walls are perfect for sheeting alongside existing buildings. The special drill bits make it possible to drill tightly against existing buildings.
  • For deep construction pits with heavy additional loads, we use ground anchors or jack posts for extra stability.
  • Thanks to the polystyrene templates for the guide beam and a manoeuvrable machine, the pile wall shape can be freely determined.
  • A secant pile wall can be installed in virtually any subsoil. Lowering the phreatic zone is not required during execution.
  • Drilling through hard subsoil or existing masonry poses no problem at all.
Sheeting for your construction pit with secant pile walls?