NATM NATMNEW AUSTRIAN TUNNELING METHOD

By ADIL BIN AYOUB

41-CE-13B.Tech

CIVIL ENGINEERINGSchool of Engineering & Technology, BGSBU

Rajouri J&K

CONTENTS

1. HISTORY OF NATM

2. DEFINITION OF NATM

3. BROAD PRINCIPLES OF NATM

4. SUMMARY OF THE PROCEDURE IN NATM

5. SEQUENCE OF EXECUTION OF NATM

6. CONCEPT OF 3D MONITERING

7. CONCLUSION

HISTORY OF NATM

The term New Austrian Tunneling Method

Popularly Known as NATM got its name from

Salzburg (Austria).

It was first used by Mr. Rabcewicz in 1962. It got

world wise recognition in1964.

The first use of NATM in soft ground tunnel in

Frankfurt (Europe) metro in 1969.

DEFINITION OF NATM

The New Austrian Tunneling Method is a support

method to stabilize the tunnel perimeter by means

of sprayed concrete ,anchors and other support

and uses monitoring too control stability.

Main idea is to use the geological stress of the

surrounding rock mass to stabilize the tunnel

itself

BROAD PRINCIPLES OF NATM

Mobilization of the strength of rock mass

Shotcrete protection

Measurements and monitoring

Primary Lining

Closing of invert

Rock mass classification

MOBILIZATION OF STRENGTH OF ROCK MASS

SHOTCRETE PROTECTION

MEASUREMENTS AND MONITORING

PRIMARY LININGWire mesh and steel ribs

CLOSING OF INVERT

ROCK MASS CLASSIFICATION

Click icon to add picture

WHY NATM

Flexibility to adopt different excavation

geometries and very large cross sections.

Flexibility to install additional support measures,

rock bolts, dowels, steel ribs if required.

Easy to install a waterproof membrane.

Easy to install primary support, i.e. shotcrete.

SUMMARY OF THE PROCEDURE IN NATM

SHOTCRETING AT THE EXCAVATED AREA(PRIMARY

LINING)

PLACING OF THE WIREMESH ALONG THE FACEOF THE

TUNNEL

ERECTION OF THE LATTICE GIRDER ALONG THE FACE OF

THE TUNNEL

PERTICULAR TYPE OF ROCKBOLTING

SHOTCRETING THE WHOLE ARRENGEMENT(SECONDARY

LINING)

CONCEPT OF 3D MONITORING

3D MONITORING IS NEW TECHNIQUE USING FOR

TAKING THE RIGHT ALIGNMENT OF THE TUNNEL

OPTICAL TARGETS ARE USED FOR DETRMINIG THE

COORDINATES FOR MEASUREMENTS

THE COORDINATES SHOULD BE CHECKED DAILY

IT IS NECESSARY FOR THE TUNNEL AS BY IT WE KNOW

ANY DISPLACEMENT AND WRONG ALIGNMENTS

GeneralOptical Target

WHERE NATM IS USING IN INDIA

PRESENTLY IT IS USING WIDLELY IN

KASHMIR RAILWAY PROJECT

THEY ARE USING IT IN THEIR TUNNELS

LIKE IN PIR PANJAL TUNNEL , T-74R, T-

48 ETC

NATM approach of design and execution of the tunneling in soft ground is

advantageous and scientific way in comparision to the old way of tunneling. This

system monitors rock mass deformation and design the support system with

reference to the rock mass type .

CONCLUSION

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THANK YOU FOR YOUR ATTENTION