bored wall pile concrete

Bored Pile Walls Explained

With many different piling methods available – from CFA piling to mini piling, it can be difficult to know how to differentiate them from one another. If you’re having any kind of groundworks construction, make sure you discuss your options with a qualified piling contractor, as the type of work will depend on the soil conditions and space available.

Here we’re going to look into bored pile walls.

What is a Bored Pile Wall?

Bored piling is a commonly-used piling method. It transfers the load to the layers of surrounding soil or rock that have sufficient bearing capacity in order to provide support to a structure. The removal of spoil forms a hole for a reinforced concrete pile which is then poured in situ, often using the CFA piling technique. A bored pile wall is when a wall is constructed using this method.

There are three bored pile wall systems:

  • Contiguous pile wall
  • Secant pile wall – hard/soft or hard/firm
  • Secant pile wall – hard/hard

The type of bored pile wall will depend on a variety of factors including surrounding soil type, construction time and cost. Here, we’ll look at each bored pile wall system in a little more detail.

Contiguous Piling

When rows of piles are inserted close together they can be used to form retaining walls. This is common when constructing basements, underpasses or cut and cover tunnels. If the piles are constructed so that they are touching they are called contiguous piles, and they can then be grouted to form a watertight wall.

Secant Wall Piling – hard/soft or hard/firm

Secant piling is when there is no gap between piles as a wall is made of interlocking bored piles. This method is a cost-effective and fast solution for when short-term water retention os required. Firstly, primary piles are constructed using a ‘soft’ or ‘firm’ concrete mix. Next, secondary piles, made of structural reinforced concrete, are installed between these primary piles with an interlock of around 150mm. This type of wall may need a reinforced concrete lining wall in order to strengthen it.

Secant Wall Piling – hard/hard

This piling method is very similar to the above, but the primary piles are instead constructed in higher strength concrete. They also may be reinforced. Tools with specially designed cutting heads are used to cut the secondary piles as these are also made with a structural concrete. Due to the type of hard concrete being used, it’s often not necessary to provide a lining wall

Advantages to Bored Pile Walls

There are many advantages to constructing a bored pile wall. They include:

  • It is adaptable to different types of wall layouts
  • Can be used for a range of different wall thicknesses
  • Easy to install in restricted space e.g. reduced headroom
  • Can be installed in difficult ground conditions
  • Minimum bulk excavation

There are a few disadvantages to pile walls, for example, it can be difficult to completely waterproof the space between the joints, and they can be more expensive compared to other methods such as sheet piling.

Dart & Co Piling Contractors

If you’re looking for a piling contractor, give one of our experts a call. We are experienced in various piling methods and used to working on commercial, industrial and private properties. Give us a call on 08002061563 or fill out our contact form to request a response.

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