For a selection of underpinning needs at restricted access sites, or sites with poor ground conditions, Mini Piling or Micro Piling is used. These are alternatives for regular piling methods that have been adapted for specific purposes where regular methods are insufficient.
Mini piling is not just utilised for home underpinning either; they can also be used on roads, bridges and tower projects that have difficult or restricted access, which is becoming more and more common in inner city expansion plans where space is at a premium. They are also more efficient in areas where there are environmental issues and the full depth of regular piles can cause disruptions.
Mini piling has the benefit over regular piling solutions due to the fact that they can be installed in sites that are subject to both width and height restrictions, even when the restrictions are as low as 2.3m.
Common methods in mini piling
Bottom driven steel cased
These mini piles, built up of a closed-ended thin walled steel tube, are driven in lengths of 2-6m. They are hammered into the soil using an internal drop hammer on to the dry concrete plug. The tubes are then joined by a full but non-structural fillet weld before being filled with high slump concrete or grout and a singular bar or cage is inserted for strength.
Open Hole Auger
For applications of cohesive soil such as firm stiff clays or soils susceptible to ground heave as well as ground with low water tables but can allow the pile bore to stay open, open hole auger is used. In these cases, a plastic-coated liner is installed to depth. This is then filled in with concrete from the top as the casings are removed.
Top Driven Steel/Precast
If piles are required in an area with poor ground conditions and restricted access a technique known as top driven mini piling is used. These are used as they can replace bottom driven piles which are unsuitable for the location whilst offering a high load capacity.
Rhino Piling specialises in mini piling in Manchester, contact the team now for more information.