Emmer Green

EFFICIENT PROBING WORK DELIVERS SAVINGS FOR CLIENT AT HISTORIC CHALK MINE SITE

Project Description

Data  47 probing positions at 70mm diameter to 25 metres below ground level in a 6x6m grid
Client  Tilbury Douglas
Type of contract  Design and build contract
Construction period  January 2024

Since the Middle Ages, the Reading area has been known for its brick and tile production. Its geology ensures its prime position for this process with both chalk and clay found in the area. In 1977, an extensive chalk mine was discovered in the Emmer Green area, with evidence of work for chalk extraction in the early 18th century, all the way through to occupation during the Second World War for storage.

At Emmer Green an existing reservoir needed routine inspection work. This meant that a new reservoir had to be constructed nearby to store the current water resource and allow the existing reservoir to be drained, to ensure water supply was not affected for the surrounding area.

The chalk mines and interlinking tunnels are not well documented, and the microgravity survey conducted on the proposed development area identified anomalies 20-25m below ground, but the exact nature of these was inconclusive. This meant that there was a risk of a tunnel and/or voids being present below the new reservoir which could lead to longer-term void migration and ground collapse underneath the new reservoir. This could have  a catastrophic impact on the new reservoir, and the release of any water could further exacerbate the voiding in the surrounding area, potentially affecting the existing reservoir.

Aarsleff were approached by Tilbury Douglas to provide input and pricing advice for a piled slab solution consisting of 55 600mm diameter piles. This proposed solution would found below any potential chalk mine tunnel at a depth of 35m. This also had to include the option for casing through tunnel voids which was a solution in excess of £500,000 with casing allowances.

After analysing the documentation, Aarsleff instead suggested we mobilise to initially undertake probing to try and define the presence or absence of the suspected mines and therefore understand the full impact of any theoretical workings. This would allow us to then map and model a significantly more cost-effective drill and bulk fill grout solution if required based on the findings, rather than the costly original piling scope.

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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.

Our plant workshop offers a range of services designed to ensure your plant works for you. Whether it’s manufacturing and fabrication of equipment for long-term needs or hire so you can complete something specific.