CPD Specifier May 2015 issue September 2014 | Page 34

Structural Repair

Minding the gap

Oxford Hydrotechnics use advanced grout injection techniques to control
soil washout in pile gaps on a high profile, London project.
H2OX were contacted by the client after soil washout was discovered in
below water table locations, in gaps between secant piles.
Excavation had commenced on the project; however, works were halted
as a result of the issue. Previous methods of dealing with the issue had
included backfilling in one location and casting concrete across another.
All work undertaken at the site was deemed sensitive as the rear face of
the piled wall was within a few metres of the London Underground network, meaning that any work carried out by Oxford Hydrotechnics would
have to acknowledge and negate any risks to the rail structure.
Oxford Hydrotechnics’ solution was to inject a highly flowable, quick
setting grout, into the pile gaps, filling up the voids and preventing further
washout of soils and gravels.
H2OX’s P200 soil stabilisation resin was also used to stabilise mobile
ground around the piles using a soil permeation technique, whereby resin
is injected and allowed to fill the pores within the ground, before setting to
create a solid mass.
Within twenty four hours, the soils in front of the pile gaps were able to be
excavated, allowing the project to continue and preventing further costly
delays to the client’s schedule.
The success of the project resulted in Oxford Hydrotechnics being asked
to continue working on site, sealing any residual leaks that appeared
within the perimeter secant piled wall using hydrophobic polyurethane
resin injection, a process that closes off flow paths within structures using
a lightweight foam.

Leak Sealing - Ground Stabilisation - Void Filling - Structural
Repairs - Concrete Repairs - Cement Grouting
OXFORD HYDROTECHNICS

TEL: [phone]

WWW.H2OX.NET
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READER ENQUIRY NO: 47