A very large part of the static problems of our buildings are due to the particular characteristic of clayey soils of showing variations in volume as their humidity varies.
These humidity variations occur seasonally depending on the climatic trend; furthermore, contexts are frequently complicated by various surrounding factors such as the presence of large trees, paved courtyards alternating with green areas, particular slopes of the land, embankments, partial underground floors (lame buildings), sewer leaks, etc. . which locally alter the soil moisture values.
Drying of the soil corresponds to a shrinkage (decrease in volume) and consequently a collapse of the structure while hydration corresponds to a swelling and, therefore, an elevation.
All those circumstances that cause uneven variations in the water content of the foundation soils challenge the structures and can trigger instability phenomena.
Up to now, this type of instability has been solved by transferring loads to deeper layers of soil, and therefore not affected by variations in humidity, creating various types of piling.
These interventions are generally expensive and invasive axes as they affect all the load-bearing structures and require accessibility with even massive equipment on both sides of the walls. Furthermore, since in most cases the buildings are not equipped with reinforced foundations, to connect the piling to the masonry it is necessary to proceed in advance with the execution of reinforced concrete perimeter curbs in which to abut the poles, with excavations, demolitions and reconstruction of sidewalks exteriors and basement floors.
More recently, methods based on injections of resins under pressure have also been adopted, but these have often not led to the hoped-for success.
In the context of the study of the static instability of a building, if the situation is caused by shrinkage and / or swelling of the foundation soil, the HBC method is a winner.
The HBC method is also very advantageous also implemented as a preventive measure in the case of new constructions where the foundation level falls to depths that are still affected by seasonal variations in the water content (see point 6.4.2 NTC 2008).
the advantage is twofold as, on the one hand, it resolves the uncertainties related to the determination of this depth which, however, can vary over time and, on the other, avoids the adoption of particular measures in the foundation that are economically more burdensome (piles, foundations particularly rigid, etc.).
HBC System description
The purpose of the system patented by us is to keep the humidity of the foundation soil of the damaged building constant over time in order to avoid subsidence and differential swelling and, consequently, to heal the static instability originated by them.
The soil is hydrated by means of water diffusion devices fed by an adduction system and a control system.
Depending on the morphological characteristics of the building and the area of the grounds, the access possibilities, the peculiarities of the load-bearing structure, the type of foundation soil and its geotechnical characteristics, the type of diffusers and their positioning will be decided and the '' optimal adduction and control system.
The diffusion devices can be made by means of partially perforated pipes of suitable material and diameter fixed in the ground by drilling and / or beating with or without inclination, or by means of wells, ditches, trenches, tunnels of suitable dimensions.
The adduction system can be automatic, semi-automatic or manual and will consist of a network of pipes, of suitable material and diameter, fed by a water source, while the control can be mechanical and / or electrical / electronic. It has the function of supplying the necessary water to the diffusers and of checking that it is kept within predetermined levels.
The consumption of water is minimal so the system is usually connected to the municipal waterworks but nothing prevents the use of any available source.
The plant is equipped with the inspection wells necessary for calibration, maintenance and punctual operation checks.
Hydro Buildings Consolidation s.r.l.
Via Alessandro Tiarini, 27/A - 40129 - Bologna - Italia
C.F. / P.Iva: 02836401204
Tel: 342 832 8237 - 051/6350845 - Fax: 051/6354238
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Typical shrinkage cracking of clayey soils
Sub-horizontal drilling with no-dig technique (without excavation)
HBC system with vertical diffusers in Plan
HBC system with horizontal diffusers in Plan