The Atal Tunnel is a 9.02 km highway tunnel that runs under the Rohtang Pass in the Himalayas. It connects Manali to Lahaul and Ladakh and reduces travel time significantly. Construction began in 2010 using the New Austrian Tunnelling Method and involved overcoming challenges like inclement weather, unstable geology, and water ingress. The tunnel enhances national security by providing faster supply routes to the Chinese border. It opened for traffic in 2020.

1. ATAL TUNNEL CONSTRUCTION PROCESS

2. Atal Tunnel is a highway tunnel built under the Rohtang Pass in the eastern
Pir Panjal range of the Himalayas on the Leh-Manali Highway in Himachal
Pradesh, India.
At a length of 9.02 km, it is the longest tunnel above 10,000 feet in the world
and is named after former Prime Minister of India, Atal Bihari Vajpayee.
PROJECT DESCRIPTION
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Project Rohtang Pass Highway Tunnel
Location Himachal Pradesh,India
Client Border Road Organisation (BRO)
Contractor Strabag AG-Afcons JV
Consultant D2-ICT JV

3. INTRODUCTION
The Atal Rohtang Tunnel is a remarkable infrastructure project that will connect the Lahaul-Spiti valley to the tourist town of
Manali in the northern state of Himachal Pradesh, India. The tunnel will also form part of an all-weather access route to the
mountainous regions of Leh and Ladakh in Jammu and Kashmir Atal Tunnel, Rohtang is named after former Indian Prime
Minister Atal Bihari Vajpayee, is a highway tunnel built under the Rohtang Pass in the eastern Pir Panjal range of the
Himalayas on the Leh-Manali Highway.
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4. 2000
The project was
announced by the then
Prime Minister Atal
Bihari Vajpayee on 3
June 2000.
The foundation stone of the
project was laid on 28 June
2010 by Sonia Gandhi in
her capacity as the
Chairperson of National
Advisory Council.
2010
Two years after the start
of the project, 3.5 km of
the tunnel digging had
been completed.
2012
more than 4 km of the tunnel had
been dug. However, about 30 m
portion of the roof of the tunnel
collapsed and the digging had to
be stopped.
2013
4.4 km of the tunnel, i.e.,
half of 8.8 km planned
length had been dug.
2014
2016
As of December
2016, 7.6 km of the
tunnel digging had
been completed.
it was decided to allow
patients to be carried through
the under construction tunnel
only in emergency. Civilians
were not allowed to enter the
tunnel before completion due
to risks of falling rocks, lack
of oxygen in the tunnel
2017
the tunnel was used for
evacuation of people
stranded in Lahaul after
sudden spell of bad
weather blocked Rohtang
La due to snowfall
2018
Himachal Road Transport
Corporation bus entered
tunnel. The bus service
operated for next five winter
months for residents of Lahaul
and Spiti valleys. Private
vehicles were not allowed
through the tunnel
2019
Sept 2020: 100%
completion of project.
Oct 2020: The tunnel was
inaugurated by the Prime
Minister, Narendra Modi on
3 October 2020,
2020
TIMELINE

5. Rohtang Pass Tunnel Details:
Shape (cross-section) of the tunnel: Horseshoe
● Finished width: 10.00 m (32.8 ft) at road level.
● Construction technique: Drill & Blast with
NATM
● Overburden: Maximum 1,900 m, average more
than 600 m
● Emergency tunnel: A 2.25 m high and 3.6 m
wide emergency tunnel is integrated into the
tunnel cross-section beneath the main
carriageway.
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6. SIGNIFICANCE
The project is even more significant due to the rising tensions on the eastern front with China. Since May
2020 , the procession of Army trucks through the Rohtang Pass has been almost ceaseless, as men and
material are ferried to the flash points in Ladakh. Not only does the tunnel mean quicker supplies, but
also that Army convoys are no longer hostage to the vagaries of nature and snowfall
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7. Challenges faced for
execution of The Atal
Rohtang Tunnel
➔ The most challenging task was to continue the excavation during heavy snowfall in
winter. Excavation for tunnelling was done from both ends.
➔ However, as Rohtang pass closes during the winter, the north portal was not
accessible during winter and the excavation was being done only from the south
portal in winters.
➔ Only about one-fourth of the entire tunnel was excavated from the north end and
three-fourths was excavated from the south end. There were more than 46 avalanche
sites on approaches to the tunnel.
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➔ Other challenges to the progress of the tunnel included difficulties in disposing
more than 800,000 m³ of excavated rock and soil,heavy ingress of water (as much
as 3 million litres per day in June 2012) that required constant dewatering, costlier
treatment and slowed the progress of excavation from 5-metre per day to just half a
metre a day and unstable rocks that slowed blasting and digging.
➔ A cloudburst and flash flood on 8 August 2003 killed 42 labourers who were
building the temporary access road.

8. 8
● At 9.02 km (5.6 mi) length, the tunnel will be one of the longest
road tunnels in India and is expected to reduce the distance
between Manali and Leh by 46 km (28.6 mi).
● The tunnel is at an elevation of 3,100 metres (10,171 ft) whereas
the Rohtang Pass is at an elevation of 3,978 metres (13,051 ft).
● Atal Tunnel, the horseshoe shaped single-tube, double-lane tunnel
has many firsts
● It is also the country’s first tunnel to have an escape tunnel within
the main tunnel because of the topography
● This is also the first tunnel to deploy the Rowa flyer technology,
which allows engineers to work at inverted levels
● The tunnel will provide all-weather connectivity to remote border
areas of Himachal Pradesh and Ladakh which otherwise remain
cut-off from the rest of the country for about six months during
winters
● The tunnel has consumed 14,508 metric tonnes of steel and
2,37,596 metric tonnes of cement, and excavated out 14 lakh cubic
metres soil and rocks, using the drill and blast technique for
excavation
● The New Austrian Tunnelling method for construction adopted for
Standout features of The Atal Rohtang Tunnel

9. 9
The Tunnel has ample safety features built into it. Some
of the key safety features are
● Tunnel entry barriers at both portals.
● Telephone connections at every 150 Mtrs for
emergency communication.
● Fire hydrant mechanisms at every 60 Mtrs.
● Auto incident detection system with CCTV
cameras at every 250 Mtrs.
● Air quality monitoring at every 1 Km.
● Evacuation lighting / exit signs at every 25
Mtrs.
● Broadcasting system throughout the tunnel.
● Fire rated Dampers at every 50 Mtrs.
● Cameras at every 60 Mtrs.
Safety Features

10. 10
The principal support system for the tunnel will be a combination
of fibre reinforced concrete and rock bolt. Yieldable steel ribs will
be used as additional support in poor rock areas. The tunnel will
have semi-transverse ventilation with fans to circulate air. The
long distance of the tunnel and the high altitude have necessitated
the special ventilation system. Construction of one of the two
access roads was completed in 2005. The road connecting the
south portal of the tunnel to Manali is 2.7km long. It will have 18
avalanche protection structures. The 23.8km north portal road will
connect the tunnel to Manali-Sarchu road. The two roads are
estimated to cost Rs1.8bn ($38m). The approach roads will
initially help in carrying the construction material to the site. They
will be later developed to meet the specifications of a National
Highway double lane. It is 8,802-metres long and about 3,000
metres above sea level. The single tube bi-lane tunnel, 5.5 metres
high, was bored through solid rock nearly two kilometres under
the Rohtang Pass.
Construction method adopted for the Atal Rohtang Tunnel

11. NATM
(New Austria Tunnelling Method)
The feasibility study for the Atal Tunnel was first done in 1990. The
foundation stone for the access road to the south portal of the tunnel was
laid on May 6, 2002. The first blast took place in 2010 and the last blast
in 2017. The tunnel was constructed using drill and blast NATM (New
Austria Tunnelling Method) techniques.
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 to control stability.
Main idea is to use the geological stress of the surrounding rock mass to
stabilize the tunnel itself
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12. 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.

13. Broad Principles of NATM :
➔ Mobilization of the strength of rock mass - The method relies on the inherent strength of
the rock mass being conserved as the main component of tunnel support. Primary
support is directed to enable the rock to support itself.
➔ Shotcrete protection - Loosening and excessive rock mass deformation should be
minimised by applying a layer 25-50mm of sealing shotcrete immediately after opening
of the face.
➔ Measurements - Every deformation of the excavation must be measured. NATM
requires installation of sophisticated measurement instrumentation. It is embedded in
lining, ground such as load cells,extensometers and reflectors.
➔ Primary Lining - The primary lining is thin.It is active support and the tunnel is
strengthened not by a thicker concrete lining but by a flexible combination of rock bolts,
wire mesh and Lattice girders.
➔ Closing of invert – Early as far as possible closing the invert so as to complete the arch
action and creating a load-bearing ring is important. It is crucial in soft ground tunnels
➔ Rock mass classification - The participation of expert geologist is very important as the
primary support as well as the further designing of supports etc during the excavation of
rock requires the classification of the rock mass.
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14. 14
1. Concrete technologies – Products range from super-plasticizers to
accelerators and retarding agents to “accessory” products, dedicated to
every type of underground shotcrete and concrete applications
2. Injection systems, consolidation and anchoring – A complete range
of ready-to-use cementitious mixtures, cement-free mixtures and
chemical resins for underground injection in different types of rock, soil
or concrete structures to improve the properties of the ground, stop
water leakages, improve internal cohesion, anchoring, bolting etc.
3. Waterproofing systems – A wide range of waterproofing systems for
all water conditions: from synthetic geomembranes and spray-applied
waterproofing membranes to complementary products for
waterproofing systems
4. Renovation, maintenance and repair technologies – Products for
renovation, maintenance, repair and waterproofing activities, ready-to-
use shotcrete and injection products.
5. Coating underground constructions – Finishes for coating
underground constructions as protective paints, cementitious mortars
and innovative technology for installation of ceramic liners.
6. Mechanised tunnelling – A complete range of products and on-site
technical service to support clients throughout all underground projects,
from start to finish.
MAPEI
TUNNEL
PRODUCTS

16. Contractors for Atal Rohtang Tunnel
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● The construction contract of the tunnel has been awarded to Strabag-Afcons, a joint venture between India-based Afcons
Infrastructure and Austria’s Strabag.
● The contractors were selected after the project was approved by the Indian Cabinet Committee on Security in September 2009.
● Australia-based SMEC (Snowy Mountains Engineering Corporation) will provide design and project management services until
completion of the project.
● The feasibility study for the project was done by Rail India Technical & Economic Services (RITES).

17. References
https://www.constrofacilitator.com/the-atal-rohtang-tunnel-a-look-into-the-construction-marvel/
https://www.constructionworld.in/cement-news/What-is-Atal-Tunnel/24172
https://www.dnaindia.com/india/photo-gallery-atal-rohtang-tunnel-2846977/rajnath-singh-reviews-final-preparations-2846982
https://www.constrofacilitator.com/the-atal-rohtang-tunnel-a-look-into-the-construction-marvel/
https://en.wikipedia.org/wiki/New_Austrian_tunnelling_method
https://discoverkullumanali.in/atal-tunnel-rohtang-tour-package/
https://navbharattimes.indiatimes.com/india/atal-tunnel-inauguration-today-by-pm-narendra-modi-check-map-route-and-distance-from-
manali-to-leh/articleshow/78456246.cms?story=1

18. THANK YOU