It seems obvious that the main problem of underground structuresin addition to the static part, is made up of risks Of infiltrations of the percolation waters, of ascent widespread and possibly aquifer. Problems and solutions
then change in relation to the interventions on New buildings and on theexisting.
On New buildings It is easier to intervene, as you can act directly from the outside, isolating the structures in the ascent; more problematic, however, is the intervention in conditions of existing structureswhere the Foundation rests directly on the ground.
By acting on the new construction, the most used static construction system that performs this function is constituted by reinforced concrete technology, both for the foundations and for the construction of the walls against the ground.
Before carrying out the underground construction, for any intended use, it will be necessary to provide forwaterproofing of the structural parts against land, adopting two possible systems.
The difference between hot and cold places
In the case of Cold rooms, not heatednot existing the need to isolate, it will be sufficient to waterproof the structures by acting from the outside and, therefore, operating on the ground of the ground or Magrone, before the execution of the foundation jet and the walls in elevation. In this case, the plane waterproofing will exceed beyond the perimeter and will connect with the sheath that will be placed on the vertical wall against the ground, until it escaped from the ground and interact under the thermal coat, if the latter is present.
Instead of heated underground premisesit will be necessary to isolate as well as waterproofing the entire structure against Earth, wrapping it with a solution of continuity, from the top to the vertical, acting with two possible solutions:
- using cell glass in compact panels, glued in adherence to static structures;
- adopting cell glass gravel.
These two solutions both constitute a system of isolation-permeable that Avoid the realization of the aerated vespaio.
Green solution for existing underground rooms
In cases of renovation of existing celled premisesthe problems that are generally pose are the same that are detected for new buildings, that is, having to isolate from water, from humidity, radon gas and, in some cases even thermally. Unlike the new construction, however, these problems they are not always resolved to the root And they must be addressed from the inside, with the application of materials, which necessarily cloils useful space. The humidity present, if it is of a widespread nature or coming from the percolation of rain waters, generally does not constitute an arduous problem, but must still be solved.
A green and tested system for this problem is the application of materials such as the cellular glass in the slab for the floor and the football silicate for the wall. The isolation of the floor with cell glass blocks the passage of humidity from the subsoil and isolates thermally. The function of the wall silicate wall silicate, however, supports the humidity that infiltrates the walls, maintaining the dimensional stability of the coating material. Even in the presence of a lot of humidity, the calcium silicate panels absorb water, and then gradually release it for a long time in the internal environment.
However, in these cases, it is necessary that the premises, thus treated, are Periodically ventilatedto avoid excessive accumulations of relative humidity in the air.
Another solution for underground rooms with perimeter closures
Without prejudice to the need to counter the push of the earth of excavation With a static reinforced concrete structure, there is the possibility of buffering the underground volume with other solutions that use less impacting materials than the waterproofing membranes. In the case of the formation of underground premises, the excavation must be enlarged to allow the addition of a space that acts by Scannafosso, in addition to the static wall against earth.
The scannafosso must be completely free from dimensions in its underground volume, well ventilated, designed with a width suitable for the passage of people, with a concave plan, equipped with helmet and pipes for water collection Meteoric.
