One side of an industrial building had settled by 20 cm and needed strengthening to prevent further settlement. The consequence of the settlement was cracks in the load‑bearing walls and foundations. The first 4 metres of the foundation beneath the concrete footings consisted of sand and mud, which tended to self‑compact because the soils in the excavation had been dumped and not properly compacted. At 4–8 metres below the foundation level, the soil conditions were more suitable for foundation strengthening solutions, since more hard clay was present. In this area, the URETEK contractor injected geopolymer and improved the soil conditions (created a virgin soil support) so that the polymer columns would achieve good support and safely transfer the loads from the concrete footings. The building is designed to stand on 10 concrete footings (columns). The foundation soil was strengthened as a result of the project to eliminate further settlement and stop further damage to the building structures.

Task
URETEK strengthened the load‑bearing structures of the concrete footings with 40 x 4‑metre geopolymer columns. The columns were formed directly under the footings to a depth of support on the dense foundation.

Technology applied:
For this facility, the patented URETEK DEEP INJECTIONS® technology – the deep injection method – was chosen. This technology made it possible to reduce the number and size of voids in the embankment by filling the space between ballast layer particles, significantly increasing strength. This was achieved by injecting a rapidly expanding polymer composition with high pressure upon expansion.

Thanks to precise studies, the areas most subject to stress were identified, and injection points were concentrated there. Injection tubes with a diameter of 12 mm were installed in specially drilled holes in the embankment. To accurately distribute the injections, tubes of different lengths were placed into each hole.

Result
Train traffic on this section was not closed during the repair and restoration work, but for safety reasons the train speed was reduced to 20 km/h. Overall, the entire operation took about 15 working days, including drilling and grouting operations.