Foundation consolidation with expanding resins

Cracks and lesions, symptoms of subsidence in the foundation, here’s how to consolidate a ground

I foundation subsidence are increasingly widespread on Italian territory, also as a result of all the changes to which the soil is subjected.
Among the main causes that generate such collapses are the hydrogeological disastersi climate change and the extreme events of drought e floods which intensify every year and tend to weaken the soil consistency of foundation.
In addition to the cause Of natural originone must not underestimate all the problems related to losses in the water networks e sewers present in the urban subsoil.

These pipes are now dated and sometimes are not maintained properly: in fact, in some cases excessive leaks occur from these pipes, which wash out and soften the foundation soil, thus causing subsidence.

Cracks and subsidence lesions in SYSTAB foundations

The mirror of these problems on the surface is the presence of structural cracks and lesions on the walls, due precisely to a lowering of the ground and the foundations. These lesions and cracks generate a real crack patternwhich must be kept under control to prevent a simple injury from leading to a sudden collapse.

To avoid such episodes, it would be necessary to keep under control the structures and any cracks that may be created by trying to understand their origin and carrying out constant maintenance of the building in all its parts, even those not visible, such as sewers and foundations.

Foundation Consolidation: How to Consolidate Foundations

The types of intervention that can be adopted to operate a good consolidation in foundation there are two:

• consolidation of the ground-foundation node with injection of expanding resins;
• deep subfoundations with steel foundation micropiles that transfer loads deep into stable soils.

The first thing to do after identifying the cause of the collapse is to stabilize the building by trying to make it safe again.
One of the technologies that has become most popular in recent years, especially since 2000, is the consolidation of the foundation soil node with injection of expanding resinsan intervention defined as very effective and minimally invasive.

Laser-controlled injection phase of the SYSTAB structure

A leading company in this sector is the SYSTABspecialized in the consolidation of foundation structures with low-invasive technologies.

Consolidation with injections of expanding resins is the ideal solution when you need to intervene quickly and effectively in delicate contexts, such as historic buildings made of masonry, or in contexts in which theintervention must be less invasive possible, such as finished and inhabited civilian homes whose subsidence affects both the perimeter walls and the internal load-bearing walls.

Foundation subsidence: how to consolidate with expanding resin injections

The SYSTAB system with injection of consolidating resins slow expansion is a very efficient technology in the consolidation sector and is based on the use of resins at different density and different expanding power, which are injected directly into the ground beneath the foundation, through 25 mm perforations and which allow for a significant improvement in the characteristics of the foundation soil, through the compaction induced by the thrust exerted by these mixtures.

The intervention is considered low invasive precisely because these injections can also be performed using manual equipment that can be easily used even inside a building, in cellars, without carrying out excavations or demolitions of any kind.

For this reason, the construction site is considered to have a very low impact, extremely fast and particularly suitable both for resolving differential settlements and for increasing the load-bearing capacity of the ground in view of elevations or for seismic adaptation.

Foundation consolidation, technical detail – SYSTAB

It is important to point out that this type of intervention is carried out with full respect for the environment and the nature of the subsoil: in fact, the resins used I am eco-friendlyare injected under constant laser control and do not alter the hydrogeological regime of the subsoil, guaranteeing the total absence of contraindications.

For optimal effectiveness and durability over time, after checking the nature of the soil with suitable geological surveys, the most suitable technique is chosen, then a predefined number of injections are performed, distributed evenly along the length of the face to be consolidated.

The number of injections will be established from time to time also based on the depth of the foundation, the type and degree of subsidence it has undergone and also based on the type of load to be supported.

Subsequently, the structure is subjected to continuous monitoring with some laser levelsso as to monitor the intervention carried out and also evaluate its effectiveness by comparing the penetrometric tests carried out pre and post injection.

Detail of SYSTAB internal wall injection holes and tubes

Using injections with slow-expansion resins you will have:

• a considerable filling of the cavities present in the foundation soil with a notable reduction in the void ratio;
• a compaction of the soil with a large increase in its geomechanical characteristics;
• an assumption and distribution of loads, with an increase in the bearing capacity of the foundation soil;
• water insulation and waterproofing of the foundation;
• an increase in safety factors;
• a significant decrease in residual settlements.

Foundation consolidation techniques, expanding resins in detail

L’resin injection slow expansion occurs by positioning, at predefined points of the wall to be consolidated, aluminium cannulas inserted into holes of approximately 25 mm, made through the foundation.

Next, an injection is made with a specific resin for cracks in walls known as. slow expansion resina two-component liquid substance, whose exothermic reaction determines a strong expansivity of the product, with the relative generation of overpressures (on average between 400 and 600 kpa) in the soil and the rapid formation of a completely inert final solid compound.

Detail of injection pipes for consolidation of the SYSTAB foundation ground node

This compound will help fill the voids and cavities present, compacting the soil and thus reactivating its load-bearing function. The increase in shear resistance values ​​obtained in the soil occurs because the cut surfaces are filled with solidified resin.
There is then an increase in the elastic parameters and a consequent decrease in compressibility.

Following this intervention, the following was noted:

• an increase in safety loads between 35 and 68%;
• a decrease in settlements of between 30 and 75%.

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THE EDITORIAL TEAM RECOMMENDS

It is born from the skills of its technicians who boast over 15 years of experience in the sector and which has allowed the birth of a company capable of proposing cutting-edge consolidation systems for the recovery of damaged buildings, the stabilization of foundations and seismic improvement.

The solutions for the consolidation of foundations proposed by SYSTAB were created to obtain the best results with the least possible invasiveness and trying to contain costs compared to traditional ones. Consolidation techniques.

The solutions proposed by SYStab follow two lines of intervention:

• consolidation by injecting slow-expanding resins, indicated for the foundation ground node;
• the creation of preloaded micropiles in high-resistance steel can be used for deeper and certainly more invasive settlements than resins

The company offers its customers a network of highly qualified technicians, engineers and geologists, which covers the entire national territory and allows it to provide an evaluation and diagnosis completely free!

Once contacted, the experts will verify the nature and the dangerousness of the landslide, advising the most suitable solution only if and where necessary, being able to count on differentiated products and procedures. All the foundation reinforcement and ground consolidation interventions, SYSTAB are designed with extreme care and guaranteed by the experience of its managers who have been dealing with consolidations since 2000.