URETEK DEEPINJECTION®
URETEK is recognised worldwide as a leading technical specialist in the repair of subsided concrete floors and steel foundations.
The foundation transfers the load from a building structure to the subsoil. If it subsides, serious damage can occur to the structure built on top of it, resulting in cracks in walls and loose jointing and plasterwork. The cause rarely lies with the foundation itself, but usually in the subsoil, where a reduction in bearing capacity has occurred. The URETEK DeepInjection® method is used to reinforce and stabilise the subsoil beneath foundations to prevent further settlement and to repair any damage.
Principle of operation
Using the patented URETEK DeepInjection® method, the two-component expansion resin is injected directly beneath the subsided foundation, in layers and starting from the soil layer with sufficient bearing capacity. The expansion resin expands within the soil, increasing in volume (up to 30 times). The aim is to increase the bearing capacity of the subsoil to such an extent that, at any given point on the treated subsoil, the bearing capacity is significantly higher than the static load of the structure. The powerful expansion (up to 50 tonnes per m²) causes the stress in the subsoil to increase in a controlled manner, thereby strengthening the subsoil. As soon as the stress exceeds the weight of the structure above, a minimal upward movement of the structure occurs. The foundation is now stabilised. As the stress builds further, the structure is lifted. The injection process is monitored very carefully using precision laser measuring equipment, enabling the structure to be raised to the desired level with millimetre accuracy. The end result depends on the structural design.
Technical data:
- Injection depth: max. 6 metres below ground level;
- Expansion force up to 50 tonnes per m² (500 kN/m²);
- Weight of expanded resin only 150–300 kg per m³;
- Excellent dimensional stability; shrinkage less than 1 per cent per 10 years;
- Height corrections with tolerances of less than 5 mm;
- The expansion resin is FCWK-, formaldehyde- and radon-free;
Injection
Injection holes with a diameter of 16 mm are drilled through the foundation footing on the outside of the property along the façade, spaced 50–70 cm apart. An injection lance is inserted into the drill holes and connected to a specially developed injection gun. The two-component mixture is thoroughly mixed within the injection gun and injected under pressure into the ground beneath the foundations. The injections are carried out from the stable, sufficiently load-bearing layer and are performed in layers down to the underside of the foundation.
Expansion
Immediately after injection, the two components react, causing rapid and powerful expansion in the soil beneath the foundation to up to 30 times its original volume. Initially, the powerful expansion causes a horizontal build-up of stress (path of least resistance). As the stress continues to increase, a vertical build-up of stress follows. Any voids present are compressed shut.
Underfilling and Lifting
As soon as the stress in the subsoil exceeds the weight of the structure above, the foundation begins to rise. As soon as a minimal upward movement occurs, the foundation is stabilised. The injection process is monitored using precision laser measuring equipment. By carefully and gradually increasing the stress, the foundation can then be raised millimetre by millimetre. This method can also be used for the preventative treatment of foundations.
Benefits of URETEK DEEPINJECTION®
- Minimal disruption
- No pile driving
- Repair in just one or a few days
- Fast and cost-effective
- Uniform support for the foundations
- The foundation method remains as originally designed