New Austria Tunnelling Method(NATM) has been covered in the slides.

1. New
Austria
Tunneling
Method
A presentation on
Vivek Kumar R6802160

2. NATM
Not too stiff, Nor too flexible
Not too early, Nor too late

3. Principles
•Maximize the inherent resistance of the rock mass,
allowing for deformation in a way that the rock
becomes its own support
•The application of a thin layer of shotcrete to prevent
a greater deformation of the rock mass
•Systematic measuring and assessment of any tunnel
movements, in order to provide any relevant
additional support measures (bolts, steel mesh and
shotcrete)

4. Source: http://bestsupportunderground.com/natm-shotcrete/?lang=en
Fig1. Stress rearrangement around a cavity.

5. Source: https://www.youtube.com/results?search_query=new+austrian+tunneling+method+%28natm%29
Fig2. Measurement of deformation
.

6. Source: https://www.aimil.com/products/bi-reflex-targets
Bi Reflex Targets
•Used for the measurement of
deformation during Tunneling
•Bi-reflex targets consists of
reflectors on both sides is mounted
on a universal joint. The target has
a small hole at the center to allow
precise targeting
•Works very well in a Measuring
range from: 12 m to 140 meters
•Measurements are made by a
Total station/ Theodolite
Fig3. Bi Reflex Targets
.

7. •For projects with highly varying ground conditions, as
methodology can be altered according to the changes
in the geology.
•Sometimes TBM installation is difficult due to the
congestion and inadequate space at the site. In such
cases NATM is preferred as construction area required
is less compared TBM.
•NATM is mainly beneficial for small length tunnels.
Suitability of NATM

8. https://www.youtube.com/watch?v=ppjfyV2F_N8
Summary

10. Thank you