Construction & Installation Of Attenuation Tank; Installation Of Attentuation Tank; Laying Geo Textile Film And Geo Textile; Construction Of Attenuation Tank - Graf ECO BLOC INSPECT 230 Notice D'installation

8. Construction & installation of attenuation tank
8. Construction & installation of attenuation tank
8.1

Installation of attentuation tank

Chapters 7.1 and 7.2 describe how to prepare the
excavation and lay the first layer of geo textile.
8.2

Laying geo textile film and geo textile

Further steps follow laying the first layer of geo
textile.
The water-impermeable film is placed on the first
layer of geo textile, followed by another layer of
geo textile. This three-layered surround provides
protection and a water-tight shell.
8.3

Construction of attenuation tank

The next stages are as described in chapters 7.3
to 7.7.
Please note:
When setting up a retention tank, it is essential to note the groundwater level. An accumulation of
groundwater may cause uplift, resulting in damage to the system and its surroundings.
If you intend to install in groundwater, please consult with GRAF beforehand. Please provide
GRAF with the necessary information about the construction project (soil cover, groundwater
level, loading etc.) and consult on this.
Depending on the soil type, heavy rainfall may cause local rises in standing groundwater,
particularly in the filling material of the trench. When installing the retention system, check again
that no compression of the subsoil or silting-up has taken place during the construction phase.
It may be necessary to install extra drainage. GRAF will be happy to provide advice on this.
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