| The
design and construction of an anchored bored pile wall in Upper
Lias Clay to retain a site boundary for a new commercial/retail
development. |
|
Project
As part of the construction of a new commercial/retail development,
a 180m lenght of the site boundary required to be retained to a maximum
height of 8m. Maximisation of development space was a key criteria.
Accordingly, Keller Ground Engineering designed and built a permanently
anchored bored pile wall complete with reinforced concrete capping
beam. By utilisation of the patented SBMA anchor system, the number
of ground anchors was significantly less than using conventional systems.
Soil
Conditions
Ground information on the site showed topsoil overlying Upper Lias
Clay (stiff to very stiff silty clay).
Solution
This consisted of 600mm bored piles at 750mm centres with an associated
capping beam. To prop the wall through the capping beam, ground
anchors were proposed to retain a horizontal force of 140kN per
metre run using permanent SBMA anchors at 4.5m centers. The design
working load for the anchors was 730kN within the till. A
preliminary trial anchor was tested up to a maximum load of 2280kN
to demonstrate the grout/ground bond properties. This allowed detailed
design of the working anchors to be completed.
Construction
The bored pile wall was installed using CFA piling methods. The
capping beam construction immediately followed. Once the beam was
installed ground anchors were formed using rotary duplex drilling
methods. All anchors were successfully tested at the required test
load.
| Client
|
Wrenbridge
(Brackmills) Ltd. |
| Engineer
|
Tapsell
Wade & Partners |
| Main
Contractor |
Marriot
Construction Ltd. |
| Specialist
Sub-contractor |
Keller
Ground Engineering |
|
