soil nailing is method used for stabilization soil.

1. SOIL NAILING
TECHNICAL SEMINAR ON

2. OVERVEIW
1. INTRODUCTION
2. ORIGIN
3. APPLICATIONS
4. ADVANTAGES
5. LIMITATIONS
6. CONSTRUCTION SEQUENCE
7. TYPICAL SOIL NAIL DETAIL
8. MECHANISM OF SOIL NAILING
9. METHODS OF SOIL NAILING
10. EXAMPLE
11. CONCLUSION

3. Introduction
 Soil nailing is A ground stabilization technique
that can be used on either natural or excavated
slopes used to reinforce and strengthen existing
ground to make it more stable
 It involves drilling holes for steel bars to be
inserted into A slope face which are then grouted
in place
 Mesh is attached to the bar
ends to hold the slope
face in position

4. Origin
 Soil Nailing evolved from the new Austrian
Tunneling method which is a system for
underground excavation in rock.
 This concept of combining passive steel
reinforcement and shortcrete has also been
applied to the stabilisation of rock slopes since
the early 1960’s.
 The first appilication of soil nailing was
implemented in 1972 for a rail road widening
project near Versailles, France.

5. Contd…
 The technique included installing high-density
grouted soil nails into 60 ft high wall and facing it
with reinforced concrete.
 The united states first used soil nailing in
1976 for the support of a
13.7m deep foundation
exavation in dense
sility sand.

6. Applications
 Remedial measure to stabilise embankments, and
so on
 Temporary excavation shoring
 Tunnel portals
 Roadway cuts
 Under bridge abutments
 Repair and reconstruction of existing retaining
structures

7. Tunnel portal Excavation
Railway cutting Bridge abutment

8. ADVANTAGES
 They are good for confined spaces with
restricted access
 There is less environmental impact
 They are relatively quick and easy to install
 They use less material and shoring
 They are flexible enough to be used on new
constructions , temperory structures or on
remoulding processes
 The height is not restricted

9.  Not suitable for areas with higher water table
 In soils of low shear strength , very high soil nail
density may be required
 Not suitable for permanent use in sensitive and
expansive soils
 Specialist contractors are required
 Extensive 3D modelling may be required

10. Construction Sequence

12. Typical Soil Nail detail

13. Mechanism of Soil Nailing
 The soil nail system can be divided into active
and passive region.
 During the slope failure, active region tends to
deform which results in axial displacement
along soil nails which are placed across the
slip plane.
 This results in the development of tensile
forces in soil nail in the passive zone which
resists the deformation of active zone.
 This tension force results in increment of the
normal force coming on slip plane and reduces
the driving shear force.

14. TENSILE FORCE IN SOIL NAIL

15. Mechanism of Soil Nailing
Soil nails improve slope stability by:
i. Partial increase in the normal force
and shear resistance along potential
slip surface in frictional soils.
ii. Direct reduction of driving force
along potential slip surface for
cohesive and frictional soils.
iii. Soil nail head and facing provides
containment effect to limit the
deformation near slope surface.

16. Methods of Soil Nailing
 Drilled and Grouted Soil Nailing
 Driven Soil Nailing
 Self Drilling Soil Nailing
 Jet Grouted Soil Nailing
 Launched Soil Nailing

17. Drilled and Grouted soil nailing
 In this type, the holes are drilled in walls or slope
face
 Then nails are inserted in predrilled holes
 After that, the hole is filled with grouted
material such as concrete, shortcrete etc.
 Nail Dia varies from
100-200mm with spacing of
1.5m

18. Driven Soil Nailing
 Used for temporary stabilization of soil slopes
 It doesnot provide corrosion protection to the
reinforcement steel or nails
 Nails are driven in slope face during excavation
 Nail dia 19-25mm comparatively small spacing is
1-1.2m

19. Self Drilling Soil Nailing
 Hollow bars are used in this method.
 Bars are drilled into the slope surface. Grout
injected simultaneously.
 It is faster than drilled grouted nailing.
 Provides more corrosion resistance to nails than
driven nails.

20. Jet Grouted Soil Nailing
 Jets used for eroding the soil for creating holes in
the slope surface
 Steel bars installed in this hole and grouted with
concrete
 Finally , jet grouted soil nailing provides good
corosion protection for steel bars

21. Launched Soil nailing
 The steel bars are forced into soil with a single
shot using compressed air mechanism
 Installation is fast , but controls over length of
bar penetrating the ground is difficult
 Utilised to reinforce an unstable soil mass
capacity into sliding
soil
 Nail diameter is 38mm
length is around 6m

22. EXAMPLE
A stretch of the Kazhakuttam-Mukkola bypass corridor of the NH66
where soil nailing Technology was used to protection and
stability of embankment above a ht of 4m by NHAI on
Kerala –Tamilnadu border

23. Conclusion
 Soil nailing is a potential solution of land slide
problems as it is economical and also
applicable in seismic zones.
 It can solve the problem of residential area
upto a great extent.
 It can be used in wide soil types.