Applications are carried out in two distinct and successive phases according to a precise application method.

a) Surface Consolidation.

In this phase the resins are injected into the zone immediately underneath the foundations with the intent of re-establishing ground-foundation contact by filling the macroscopic holes which may be present. Furthermore, the geo-mechanical properties of the more superficial foundation ground are improved in increasing its shear resistance.

b) In Depth Consolidation

Injections are carried out more in depth and precisely in the volume of ground most concerned by the tensions provoked by the load above: the pressure bulb.
The evaluation of the size of the zone to be treated as well as the method of injection and the pattern and depth of the injections are made by a specific, case by case investigation. One must in fact take account of the significant volume, of the compressibility and nature of the ground underneath and also of the type of structure to be treated.
Each Uretek technician is supported in this phase by the considerable wealth of knowledge and experience accumulated over the years by the Uretek World Group in collaboration with eminent external specialists in the sector (Geologists, Geo-technicians and Structural Engineers). The objective of this phase is the definite consolidation of the foundation ground which will occur by means of a marked densification of the ground by:
- the elimination of large and small voids by filling and flattening;
- the expulsion of any water and air which may be present;
- the agglomeration of the disaggregated parts.

In both of the phases, the injection of resin is prolonged until verification, through continuous laser monitoring, of the beginning of lifting of the supported structure.

The process can be resumed as follows:
Once the resin injected into the ground reaches the zone to be treated, it begins to expand in all directions in developing a force greater than 50 ton/m2. Naturally, the expansion is greater in the direction in which the resin encounters the least resistance.
And so, in the first place, the resin moves and expands to where the foundation ground is weakest and has the greatest need of being reinforced.
Only in a second stage does the resin expand upwards and precisely when the surrounding ground, by now well compacted, offers more than sufficient resistance to counterbalance the weight of the ground and the structure above it.
At this point, a laser receiver anchored to the building, or any other monitoring system, indicates the moment at which the resin starts to expand upwards which determines the beginning of the lifting of the structure.
A beginning of lifting indicates that the foundation ground has reached a degree of compression and densification that makes it capable of resisting not only the static forces generated by the structure above but also the dynamic forces which develop during the lifting process and which are much greater than the static forces. This indicates unequivocally that the load bearing capacity obtained in the volume of earth subjected to the injection has reached values appreciably higher than those necessary to support the static load.
The operation is repeated in all the volume of earth to be treated so the increase in load bearing capacity is uniform.

OPERATING PHASES »