Stopping building subsidence
The most cost-effective and quickest solution for stopping building subsidence is to reinforce the unstable ground beneath the foundations using PUR injections.
In ground PUR injection, foaming polyurethane is injected into the ground to be treated using injection lances (steel pipes, Ø 12 mm) in a defined grid pattern and at several different depths.
The sketch shows a standard injection concept.
The injection lances are placed in the ground through pre-drilled holes (Ø 32 mm). Once the injection work is complete, the lances remain capped at ground level in the ground and cannot be re-injected.
The preheated synthetic resin (to 40°C) is pressed into the ground from the injection system at high pressure (up to a maximum of 140 bar). As soon as it leaves the injection pipe, the liquid resin begins to foam within a few seconds. The foaming resin penetrates further into the soil structure through its own expansion force.
Depending on the soil type, the resin penetrates the pore volume of the building ground and/or presses open flow paths. In the process, the fully expanded and hardened resin cements and compacts the building ground, reducing the pore volume and increasing the shear strength, which leads to an improvement in the load-bearing capacity of the building ground.
During the injection work, the structure is continuously monitored with laser levelling instruments. Each lance is precisely logged in terms of the amount of resin injected and the lifting reaction that has occurred.