Rotary Bored Piling is a traditional method for constructing bored piles by open hole techniques and using a short length auger attached to a Kelly bar it removes small bites of the ground bringing this bored soil to the surface before spinning off adjacent to the pile hole.

A J Hurst (Foundation Engineering) Ltd
Unit 9G2, Carcroft Enterprise Park
Station Road, Carcroft
Near Doncaster DN6 8DD

TEL: +44 (0)1302 339 300
FAX: +44 (0)1302 339 600
EMAIL: info@ajhpiling.co.uk

Rotary Bored Piling

In unstable and water bearing soils support is usually required to keep the hole open throughout the boring operation that support can be provided by casing or drilling fluids. However in cohesive soils this method is very successful and being an open hole technique it allows access to hard bands or socketing into rock at the base using alternative boring methods. It also allows open access to the completed hole to install heavy reinforcing cages which is ideal for contiguous wall piles.

CASE STUDY ONE

A developer in Sheffield wishing to build in a sloping location needed both the front and rear of the site supporting to maximize the build area in between. They had looked at using driven steel piles but noise and vibration considerations and as importantly cost considerations ruled this method out. Because the front wall needed to be self supporting for three and a half metres height, AJH piling came up with the novel idea of providing this wall free standing by using thin guage steel liners. The wall thus formed could then be excavated a further two metres before building the Flats. By backfilling this behind the freestanding wall and building a cosmetic stone wall the whole front of the site was stabilised to great effect. The pictures below show the situation immediately after installation of the piles and then later after completion of the cosmetic walls and Flats.

OTHER CASE STUDIES

Here are a couple of further examples showing the use of rotary bored piling:

In Wakefield in order to build a cellar as part of a new Working Men’s Club the contractor asked us to stabilize the adjacent retaining wall and the shops behind it to prevent any possibility of slippage. We prepared and constructed a soldier pile scheme using rotary bored piles with Universal Columns concreted in at 2m centres. Pre-cast concrete panels were then installed between the U.C. flanges as the excavation took place, we were also even able to find a cheap source of supply for these pre-cast conctrete panels.

We are currently working on a very large project in Newcastle to produce a retaining wall that will be completed in late 2008. Here are early photographs of the wall being exposed. Such a wall would not be an ideal choice to be constructed with CFA techniques not only because of the very heavy cages required but also because the very hard bands of rock to be penetrated.