| case history |
| Consolidation of a failed slope
between Prenestina New state highway and the Prenestina Old
road, Fiuggi, Frosinone, Italy |
 |
|
|
| PRODUCT |
|
TENAX TT 400 and TENAX TT 300
SAMP geogrids |
| LOCATION |
|
Fiuggi (FR), Italy |
| OWNER |
|
Comune di Fiuggi |
| PROJECT |
|
Dr. Ing. Pietro de Carolis |
| CONTRACTOR |
|
Ondino Romeo - Napoli |
|
|
problem
Fiuggi is a small town in central Italy which has for centuries
been famous for its spa waters. It is situated on sloping terrain,
with abundant subterranean water flows, in an area of seismic activity.
These factors cause numerous problems to the stability of the land
in the surrounding areas. Along the connection road between the
Prenestina Nuova state highway and the Prenestina Vecchia road,
a landslide occurred halfway down a slope with a gradient of between
20 and 30 degrees.
This area was intended for residential development and bordered
a geo-hydraulic basin which is a source of the spa waters. The landslide
front measured approximately 300 m and its depth between 10 and
15 m.
The failure surface was close to a plane and the foundation soil
had a very low bearing capacity.
solution
The landslip was consolidated using the reinforced soil technique.
The fallen soil (which consisted of silt of pyroclastic origin and
reworked clay of colluvial origin) was replaced with other materials
with better mechanical characteristics which were available on site
(volcanic pozzolan).
This was then reinforced with TENAX TT 400 SAMP and TENAX TT 300
SAMP geogrids.
The installation of the geogrids was performed, in terms of the
special demands of the project, using the "wrap-around"
method: the geogrids were laid and fixed using "U" pegs;
soil was then spread and compacted; the geogrids were then turned
over and re-fixed.
The job was extremely simple and was performed by unskilled labour
using normal soil moving equipment.
The job was completed with the addition of non structural concrete
panels (used for their attractive appearance) along the service
road, which was located half way down the slope, and at the foot
of the slope.
The problem of drainage was solved by putting coarse gravel between
the reinforced soil wall and the concrete panels, thus creating
a drainage channel.
conclusions
The consolidation of the landslip through soil reinforcement with
TENAX TT SAMP geogrids meant that:
- it was possible to consolidate the slope under difficult natural
conditions;
- it was not necessary to use foundation piles which may have
interfered with the subterranean flow of water;
- it was possible to utilise a fill soils found on site which
meant notable financial savings.
|
geo@tenax.net