Soil nailling for safe excavation
SOIL NAILLING :--
Soil Nailing is an in situ reinforcing of the soil while it is excavated from the top down. A
array of soil nails which are passive inclusions are installed in a grid that functions to create a stable mass of soil.
This mass of reinforced soil functions to retain the less stable material
behind it. In the right soil conditions, soil nailing is a rapid and economical means of
constructing excavation support systems and retaining walls.
in many applications soil nailing can be the least disruptive way to construct a retaining wall.
Soil nailing requires an unusual amount of hand work, craftsmanship and geotechnic
knowledge to construct.
The typical construction sequence begins with the excavation of a shallow cut. Then
shotcrete is applied to the face of the cut and soil nails are drilled and grouted. This sequence.
1.Creates less noise and traffic obstructions.
2. Less impact on nearby properties.
3. Allow in - situ strenthening on existing slope surface with minimum excavation and back filling, particularly very suitable for uphill widening , thus environmental friendly.
4. Allow excellent working space in front of the excavation face.
5. Can be used for strenthening of either natural slope, natural or man-made cut slopes.
1. Nail encroachment to retained ground rendering unusable underground space.
2. Generally larger lateral soil stain during removal of lateral support and ground surface cracking may appear.
3. Tendency of high ground loss due to drilling technique, particui\larly at course grained soil.
4. Less suitable for course grained soil and soft clayey soil, which have short self support time, and soils prone to creeping.
5. Suitable only for excavation above groundwater.