The document describes the process of installing a secant concrete piled wall near an existing structure. A double auger drill drives through the existing foundations and excavates soil to the required depth. Concrete is then pumped into the excavated pile while the auger and casing are extracted. Once the concrete sets, reinforcing steel can be installed before commencing further excavation. The double auger equipment allows basement walls to be constructed close to existing structures without needing underpinning work.

1. Party Wall Line
Party Wall Line
Party Wall Line Party Wall Line Party Wall Line
Double auger
drive unit with
outer casing Casing and As casing and
coring through auger drill to auger are being
the existing required depth extracted the
brickwork and before installing concrete is
foundations concrete by pumped into
pumping through the excavated
the system pile.
Existing wall
Once the concrete has
foundations to
inside of clients
been installed then the
property steel reinforcing can be
installed. 3-4 days after
completion excavation
can commence
The Double Auger equipment is specially designed to
provide basement walls close to existing structures and
maximising the available basement space.
The single action of providing one wall without the need for
underpinning makes it extremely cost effective and can
provide time savings to the project as excavation is
continuous with the frames being installed as the excavation
deepens.
Project Title
32a Ovington Square - London Sketch of construction sequence for the
Hard Hard Secant Basement Piled Walls installation of a Secant concrete piled wall
through the existing foundations.