There are various ways of creating or underpinning foundations, each of which works in the right situation. Perhaps the most broadly effective, though, especially for underpinning, is piling. This has the advantage of creating secure foundations in unstable conditions.
Piling comes in a number of different forms, depending on the challenge, and there are several ways of constructing them.
Driving a pile means that you force it into the ground, displacing the soil rather than removing it first. Driven piles tend to be stable in soft, squeezing soils, and if the soil is loose they can make it denser. A couple of effective types of driven piles are:
- Steel cased Grundomat driven piles — The Grundomat machine uses compressed air to power the hammer that drives each section of the pile into the ground. This is then connected by a spigot and socket joint to the next section, until the required depth has been reached.
- Steel cased bottom driven piles — Here the energy is delivered to the pile toe, rather than the top, which makes the system very energy efficient. This means that the machinery is relatively small, opening up access to confined spaces.
This process involves creating a hole for the concrete or grout to be poured into. It has several advantages, especially in built-up areas, since it involves minimal vibration and doesn’t need as much headroom as many other methods.
An example of this the grout injected continuous flight auger. This involves drilling a continuous flight auger into the ground, with the sides of the hole supported at all times by the auger. The grout is then poured in and the auger gradually withdrawn.
Mini piles, sometimes referred to as micropiles, are piles with a narrow diameter. They’re small, light and inexpensive, but can still carry a heavy load. Different types can be either driven or bored.
Sectional auger mini piles, for instance, are bored with multiple flight sections added down to the desired depth. The concrete can be poured in either with the flights still in place or after extracting them, depending on the stability of the soil.
Rows of piles inserted close together can be used to form temporary or permanent retaining walls. Most typically, they’re used in constructing basements, or to put up a structure close to an existing one.
These are just a few of the most common types of piling. If you have a construction or underpinning issue that piling might solve, you’re very welcome to get in touch with us and discuss options.