Reinforcement of soil layers with insufficient bearing capacity.
URETEK DEEPINJECTION®
URETEK is recognised worldwide as a specialist in high-quality technical solutions for the repair of subsided concrete floors and foundations.
Foundations transfer the load of a building to the ground. If they subside, the building above can suffer significant damage, such as cracks in the walls and the detachment of joints and plaster. The cause rarely lies with the foundations themselves, but is usually due to the subsoil, whose bearing capacity has been reduced. The URETEK DeepInjection® method reinforces and stabilises the subsoil beneath the foundations to repair damage and prevent further settlement.
How it works
Using the patented URETEK DeepInjection® method, the two-component expansion resin is injected directly beneath the subsided foundation, layer by layer, starting with the soil layer that has sufficient bearing capacity. The expansion resin expands within the ground, increasing its volume (up to 30 times its original size). The aim is to increase the bearing capacity of the subsoil to such an extent that, at every point across the treated area, it is significantly greater than the static load of the structure. The significant expansion (up to 50 tonnes per m²) causes the stress in the subsoil to increase in a controlled manner, thereby reinforcing it. As soon as the stress exceeds the weight of the structure above, there is a minimal upward movement of the structure. The foundation is now stabilised. By further increasing the stress, the structure can be raised.
With the aid of a high-precision laser measuring device, the injection process can be precisely controlled, allowing the structure to be raised to the desired level with millimetre accuracy. The final result depends on the architectural design.
Technical data:
- Injection depth of up to 6 metres below ground level
- Expansion force of up to 50 tonnes per m² (500 kN/m²)
- Weight of the expanded resin: just 150–300 kg per m³
- Excellent dimensional stability; shrinkage of less than 1 per cent every 10 years
- Leveling with tolerances of less than 5 mm
- The expansion resin contains no CFCs, formaldehyde or radon
- Average application rate of 12 m³ of foundations per working day, depending on the injection depth.
Grouting
At intervals of 50 to 70 cm, injection holes with a diameter of 15 mm are drilled into the foundation along the façade on the outside of the residential building. An injection lance fitted with a specially developed injection gun is then inserted into these boreholes. The two components are thoroughly mixed in the injection gun and injected at low pressure into the ground beneath the foundations. The injections are carried out starting from the stable soil layer with sufficient bearing capacity and applied layer by layer down to just below the foundations.
Expansion
The two components react immediately after injection, causing rapid and significant expansion in the ground beneath the foundation, which can reach up to 30 times the original volume. Initially, the significant expansion causes a horizontal increase in stress (minimum resistance). As the stress increases, there is a vertical increase in stress. Any voids present are filled.
Stabilisation and Lifting
As soon as the stress in the subsoil exceeds the weight of the structure above, the foundation begins to rise. The foundation is stabilised as soon as a minimal upward movement is achieved. The injection process is monitored using a high-precision laser measuring device. By further increasing the pressure in a controlled and careful manner, the foundation can then be raised millimetre by millimetre. This method is also suitable for the preventative treatment of foundations.
Benefits of URETEK DEEPINJECTION®
- Minimal disruption
- No pile driving
- The repair work is completed in just a few days
- Quick and cost-effective
- Uniform support for the foundations
- The layout of the foundations remains unchanged
- No point loads as with conventional shoring, but even load transfer to the subsoil
- Environmentally friendly, so it can be used anywhere