Home » Projects » Stabilisation of Shildon Coal Drops

Stabilisation of Shildon Coal Drops

Overview

The Grade 2 listed Victorian-aged masonry retaining wall, known as Shildon Coal Drop, is located in the town of Shildon, County Durham. The retaining wall was originally used as a locomotive refuelling station and the Timothy Hackworth Museum Railway line runs along the toe of the retaining wall.

Constructed in 1847, it is believed that the site, known locally as the ‘coal drops’, was the first ever attempt to mechanise the process of refuelling steam locomotives in the UK.
The structure is leaning towards the railway line and historical intervention in the form of masonry buttressing is present in front of the wall. Within the last decade, further movement of 100mm had occurred.

The Darlington Heritage Railway is planning to run trains down the line adjacent to the drops. The primary concern was the potential for vibrational stress from the trains to cause movement in the wall, risking the structural integrity of this historic site.

Geobear was contacted to use its geopolymer injection process to stabilise the historic wall and protect the asset from further movement caused by stresses from a live track.

Solution & Execution

The project involved injecting geopolymer material beneath the foundations of the wall to increase the bearing capacity of the soil and minimise the impact of vibrations that could lead to movement. The process was carefully planned, with injections targeted below the foundation, where the soil was identified as being particularly soft. The foundation depths ranged from 500 mm to a meter, and the wall spanned 120 meters, making the task both extensive and intricate.

A key challenge encountered during the project was the softer-than-expected soil in the top layers, leading to adjustments in the injection process. The project team and engineers illustrated the versatility of the Geobear solution by modifying their design on-site to counteract the soft soil.

Geobear’s technicians conducted pre-tests and post-tests every 15 meters along the wall that verified the desired bearing capacity was achieved.

Method, Low Carbon & alternatives

Geobear’s solution emits significantly less carbon than traditional alternatives. A major excavation and underpinning or piling scheme would, based on Carbon Footprint reports of similar projects, emit up to 75% more carbon.
Geobear’s method requires a minimal plant, typically one mobile unit. Our site team of eight people used hand-held drills to drill holes for injection tubes to the required depths beneath the foundations. The tubes are then installed and injections of geopolymer resin are made to specified locations. The tubes are removed and disposed of leaving the site with no spoil or notable signs of major works.

Outcome & Future Prospects

The project successfully increased the bearing capacity of the soil beneath the wall, securing the structure’s stability against potential vibrations from the heritage train line. The Shildon Coal Drops site is now poised for its next chapter, serving as a heritage site where visitors can experience the historic train route, with the assurance that the wall’s structural integrity is preserved for future generations.

Conclusion

The stabilisation work at Shildon Coal Drops stands as a testament to the importance of preserving historical sites, the challenges involved in such endeavours, and the technical expertise required to address these challenges effectively.

The project not only preserved a piece of history but also ensured that it could be safely enjoyed and appreciated by future generations. The success of this project serves as a benchmark for similar heritage conservation efforts, highlighting the importance of thorough planning, adaptability, and precise execution in the field of structural stabilisation and preservation.

Related projects

Contact Us

Please use this contact form or navigate to the contact us page and send us a message. We will respond to you within 24hrs.

Alternatively please call us on 0800 084 3503 and speak to our customer services team. Calling from Ireland please go to the contact us page.

We deliver projects on any sort of building or structure – from conservatory extension problems to 80,000m2 warehouses and road infrastructure. In most cases we will have the best solution, so get in touch today.

  • This will help us as we can look at local site conditions.
  • This field is for validation purposes and should be left unchanged.