Elan Aqueduct, Frydd Wood

INSTALLING SOIL NAILS FOR SEVERN TRENT ELAN VALLEY AQUEDUCT PROJECT

 

 

Project Description

SCOPE OF WORKS 670no 100mm soil nails, 670no head plate and nut 1250m2 steel mesh and geotextile facing

CONTRACTOR Barhale and North Midland Construction

CONSTRUCTION PERIOD 17th July 2017 – 15th September 2017

The BNM Alliance (a joint venture between Barhale and North
Midland Construction) awarded Aarsleff Ground Engineering
the contract to design, supply and install a soil nailed slope to
allow, with associated works, the launching of a TBM (Tunnel
Boring Machine) for the Severn Trent Elan Valley Aqueduct
Rehabilitation project in Wales.

The original aqueduct was built between 1893 and 1904. Fast
forward over 100 years and the aqueduct still provides drinking
water from the Elan Valley to Severn Trent’s customers in
Birmingham. The aqueduct transports high quality water
entirely by gravity. Having supplied water for over 100 years, the
aqueduct is beginning to tire in three key locations and offline
replacements are necessary.

8No test nails were installed on the 17th July. These were tested
to destruction to confirm the design prior to production works
starting. With its Klemm 806 rig, Aarsleff will then installed 670no
100mm diameter fully galvanised R32 -280 self-drilling soil nails of
6-16m in length.

In addition to the soil nails, approximately 670no head plate
and nut were supplied and fixed. The soil nailed wall has an
estimated 1250m2 area to which Aarsleff has supplied and fixed a
steel mesh and geotextile facing. Aarsleff were on site from 24th
July with completion 15th September 2017. Aarsleff showcased
its previous work in soil nail projects of similar size to the
main contractor before winning the contract to demonstrate
its technical capabilities and expertise whilst simultaneously,
assuring the client of cost, time and quality. Aarsleff Ground
Engineering has sought value engineering primarily through
optimisation of the soil nail layout and facing mesh.

The self-drilling soil nails were procured from Barnsley-based
Minova and possess a hollow bar, which is used for drilling
ether with water flush, air flush or cement grout flush and are
extended by using couplers. The standard couplers have a
design which ensures end-to-end bearing of the hollow bars to
transfer percussive energy from the top hammer to the drill bit
whilst a sealing ring in the centre stop, minimised flush spillage
during drilling. The soil nails also possesses a sacrificial drill bit.

The rig we employed is designed for the use of powerful
double head drilling units, hydrualic drifters or rotary heads.
It can also be equipped with drill masts either with feed gear
or cylinder feed systems, with the option of fitting lattice mast
extensions, the modularity of which, allows the adaption of a
variety of options, which makes the drill rig ideal for anchoring,
micro piling, jet grouting and even geothermal drilling. After
completion, two percent of all working nails will be ‘Acceptance’
tested to validate the design and provide confidence as to the
quality of the installation.

Speaking about the work for the Elan Aqueduct, Aarsleff’s
Assistant Department Manager for Ground Engineering Jonathan
Greener said: “I am pleased to secure yet another soil nail job for
such a prestigious scheme. It enables us to directly transfer all
our skills from one project to the next, allowing us to continually
improve and achieve the best results in ground engineering.”

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Case Study

A leading UK ground engineering specialist, focusing on multi-discipline excellence and value engineering. We design and deliver some of the UK’s largest ground engineering projects.

Our vision is to bring confidence to those constructing the landscape of tomorrow .

1947. Central Jutland, Denmark. Per Aarsleff borrowed 10,000 Danish Kroner from his father’s life insurance, bought an excavator, and founded Northern Europe’s leading contracting company.

Our biggest asset, our team is composed of the leading experts in ground engineering. Working with collaboration and cohesion at the core of our business, we can guarantee a quick and founded answer to all your questions.

We recruit and reward our people based on our ‘Step into the Blue’ company culture, where we embrace the core values of Life and Health, Trust, and Responsibility.

We do everything to ensure our team and yours work safely on our sites. With our core value of Life & Health, we see safety as a cultural pillar.

Our ISO accreditations are an assurance to you that we take governance seriously. Read our policies to discover more.

The projects that keep society running. Bridges, buildings, transit and rail facilities, embankment support, marine and offshore facilities, mines, airports, and water projects.

Keeping things turning. Sewage Treatment Works, Waste Water Treatment Works, Wind Farms and Wind Turbines, Biomass Plants, and Power stations.

Meeting society’s needs. Nursing and care homes, MOD buildings, Schools and Universities, and small or large-sized residential developments.

Staying on the move. Remediation, bridges, and foundation work are integral to keeping the industry running smoothly.

The landscape of the marketplace. Mega-retail sheds, distribution warehouses, University accommodation, and major supermarket and household name units.

Keeping things afloat. Ports and harbours, coastal defences, river embankments and inland waterways.

Technically trained estimators and a dedicated, in-house design team means we consider value-engineering at every stage of your project.

More than just a model, Visual Design & Construction is a tool to encourage collaboration and improve quality across all facets of a scheme.

From large commercial sheds to small residential plots, piling could be the foundation solution you need to support your project.

Issues around collapse, slipping or erosion? Our experts in retaining solutions have a broad portfolio of techniques designed to fix even the most nuanced of sites.

Tricky ground conditions or requirements? Aarsleff’s ground engineering team work on stabilisation through a varied range of techniques, bespoke to the properties of your site ground.

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