Piling represents a range of techniques by which steel or concrete are inserted into the ground by either driving or drilling down to a substantial depth. It’s used when the ground is unusable for the first couple of metres, or where a high water content makes it unstable. It can also be used as an alternative to the high costs of removing deep trench foundations.
There are many types of piling, but in recent years mini piles (sometimes called micro-piles) have become increasingly popular. So are they better than traditional methods?
The various traditional piling methods each have their roles, especially in large, open sites and large construction projects. Driven piles are particularly useful for offshore use, though they can be used on land too. Their great advantage is that, because they penetrate the ground by displacement, the soil at the toe is compacted, giving the pile the ability to support a considerable load.
Bored or drilled piles, on the other hand, are used more often in urban environments. In this system, a shaft is drilled and concrete is poured in, creating a pile in situ. They create considerably less vibration than the driving process.
Mini piling involves driving or screwing hollow steel shafts into the ground, which then have concrete or grout poured in to form a pile. Though this has similarities to the drilled pile system, the soil is supported throughout by the steel shaft, so there’s no need to add extra supports if the soil is weak. One variation is sectional auger mini piling, where the shaft is inserted in segments. This is particularly useful in settings with limited headroom.
Mini piling is often chosen for underpinning, since it requires less space for the far smaller rigs used. This also makes it useful for any project where the space is limited or access is difficult, but also in difficult ground conditions or when environmental factors make it necessary to minimise noise and vibrations.
Mini piling is also suitable for larger-scale projects, though. It’s been used successfully to support bridges, electricity pylons and offshore wind farms.
Which Is Better?
There’s no simple answer. Traditional piling continues to be the best option for large projects where a substantial load needs to be supported. On the other hand, uses for mini piling are increasing and it’s proved effective on surprisingly large-scale constructions. It’s unlikely that mini piling will completely replace traditional techniques, but perhaps it will eventually become the norm.
If you have a project that may need an expert piling service, get in touch and discuss it with us.