The document provides an overview of the Atal Tunnel project in India. It discusses the key details of the project including its location in the Himalayas, length of 9.02km, cost of 3200 crore, and ability to handle 3000 cars and 1500 trucks per day. It also summarizes the major construction challenges like dealing with the Seri Nala fault zone, ensuring alignment precision, and addressing extreme weather conditions. Safety features of the tunnel are highlighted such as telephone connections every 150 meters and fire hydrants every 60 meters.

1. ASSIGNMENT NO-1
PRESENTATION ON ATAL
TUNNEL
MANE ADITYA PRASHANT
M.TECH CONSTRUCTION
MANAGEMENT
ROLL N0- 222030008

2. CONTENT
 PROJECT OVERVIEW
 PROJECT TIMELINE
 NEED FOR PROJECT
 CHIEF ENGINEER
 STANDOUT FEATURES OF ATAL
TUNNEL
 SURVEY AND PREPARATION OF DPR
 CONSTRUCTION OF TUNNEL
 CONSTRUCTION CHALLENGES
 SAFETY FEATURES
 REFRENCES

3. PROJECT OVERVIEW
 PROJECT NAME :- ROHTANG PASS HIGHWAY TUNNEL WHICH IS NOW KNOWN AS
ATAL TUNNEL
 LOCATION :- PIR PANJAL RANGE OF HIMALAYAS
 CLIENT :- BORDER ROAD ORGANISATION
 CONTRACTOR :- STRABAGS AG – AFCONS
 SHAPE ( CROSS SECTION) OF TUNNEL :- HORSESHOE
 CONSTRUCTION TECHNIQUE :- DRILL & BLAST WITH NATM
 COST OF PROJECT :- 3200 CRORE
 LENGTH, ROAD WIDTH & CARRIAGE WIDTH :-9.02 KM, 10.5 METRE & 4 METRE
 DESIGNED FOR :- 3000 CARS & 1500 TRUCKS PER DAY AT MAX DESIGN SPEED
 DESIGN SPEED OF TUNNEL :- 80 KM/HOUR
 LONGEST ROAD TUNNEL IN WORLD WITH THE ELEVATION OF 10000 FEET ABOVE
MSL
 PROJECT CONNECTIVITY:- FROM LAHAUL SPITTI VALLEY TO OTHER TOURIST

4. PROJECT TIMELINE

5. NEED FOR PROJECT

6. NEED FOR PROJECT

7. CHIEF ENGINEER
 Chief Engineer KP Purushothaman was the man
who led the construction of Atal tunnel.
 He holds PG Diploma & MBA in Construction
Management, cracked UPSC in 1987 & worked as
a Executive Engineer in Andaman & Nicobar. He
also was the part of many important road projects
on China, Pakistan.
 He is the chief of Border Road Organization.
 3000 workers, 770 engineers, supervisors,
consultants, & contractors working at same time
24 hours in 3 different shifts.
 Under his guidance cost od 800 Crores was saved
from 4000 Crores which was the budget issued.

8. STANDOUT FEATURES
 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.
 It is also the country’s first tunnel to have an
escape tunnel at every 500m below pavement
(3.5 * 2.25)m.
 The project has almost saved travelling of
almost 46 KM.
 The project is been more significant due to
rising tensions between india and china on
eastern front. The army trucks and army
convoys can now easily travel through tunnel
and can easily overcome hostage situations.

9. SURVEY & PREPARATION OF DPR
RITES Ltd (Govt PSU of Indian Railway )along
with some geo -consults from Austrian
consultancy firm had the responsibility of Survey
and preparation of DPR. They engaged
themselves in 1990 and submitted the Phase-1
report in April 1994 which included the following
 Surface Studies including Geological, Remote
Sensing, Geomorphological.
 Construction of Exploratory Drift at both
Portals Drill for tunnel alignment and
laboratory tests.
 Fixing of Portal Locations and ground marking
of tunnel alignment.
 Preliminary design based on initial laboratory
tests. Construction planning, equipment,
survey, evaluation of construction material,

10. RITES Ltd Phase-2 Report- It was submitted
in 1996 and included the following
 Detailed report including civil drawings,
test results, and specifications & Conditions
of contract.
 HVAC and safety system with drawings.
 Design of Tunnel Section, support system,
lighting, etc.
 Preparations of Schedule of Quantities.
conditions of contract and listing of codes
 Construction methods, cost analysis, and
equipment requirement.
 Leakage, dewatering, grouting, blasting,
and support system.
 Construction schedule, supervision of
contract, and maintenance of tunnel.

11. RITES Ltd Phase-3 Report- following
aspects were covered in Phase-3
 Tunnel alignment and new South
Portal location.
 Geological and Geotechnical
aspects.( Seri Nala flow, Rock
structures & strata, seismic factors
etc)
 EIA & Traffic studies.
 Tunnel design , Ventilation system &
Project cost.

12. CONSTRUCTION OF ATAL TUNNEL
 Rohtang tunnel construction is based on the
NATM strategy. NATM works on the principle of
continuous observations made after each execution
cycle. As the Himalayan range has varying
geological conditions this is the best suited
methodology for construction of the tunnel.
 The main principle of NATM is that the
surrounding rock provides main support to the
tunnel excavated and additional support if needed
is provided to maintain the strength of rock and
prevent disintegration .
 The surrounding rock itself therefore behaves as a
structural arch which acts as a load bearing
member.

15. • The main tunneling and construction activities were
organized and carried out as under:
Top heading and half sided benching: The top heading
(or upper half) of the tunnel section is excavated first
and supported by shotcrete (sprayed concrete lining)
and benching (lower half).
Deep invert excavation: Excavation for lowest section of
tunnel i.e., floor. Section of excavation.
 Main tunnel drainage is provided and concreting is
done on egress tunnel (outlet) base slab.
 First lining kicker concreting.
Precast emergency egress structures installation.
 Pavement drainage and pit installation works.
 Second lining kicker concreting and backfilling up to
road level.

16.  Cable ducts installation and concreting
base of walkway.
 Final arch concreting over lining and
ventilation slab reinforcing and
concreting.
 The road is constructed by pavement
quality concrete with dry lean concrete
laid as base.
 Kerb installations and walkway
(footpath) works.
 Safety installations, Electrical works and
finishing works.
 Storage caverns for fire water and
turning bay caverns.

17. CONSTRUCTION CHALLENGES
1) Seri Nala fault zone: This is the longest shear zone ever encountered in a single
stretch, approximately 587.5m in any tunnel construction. The tunnel is passing
under Seri Nala, because of which weathering of rock occurs, muck along with
water started to flow from the face. Heavy inflow of water at a rate of 8000 litres
per minute was experienced. So, while tunneling through this zone, the team faced
many unexpected difficulties and overcame them using various solutions based on
the condition at that place.
 Plugging with sandbags, applying a thick layer of shotcrete is done to control the
muck flow in the tunnel.
 Certain holes are provided in the crown region for pressure relief and drainage
purposes, so that water can be channelized and removed.
 Pre-grouting is done through the previously drilled holes with OPC and micro fine
cement through a reasonable pressure as required depending on location.

19. 2) High overburden at North Portal
 Main challenge encountered is due to high stress conditions and resulting pressures due to
surrounding rock.
During excavation due to sudden release of stresses rock were prone to exhibit rock bursting and
rock squeezing around the periphery of opening.
 Even delayed release of stress along these planes caused problems like cracks in lining,
excessive stress on rock bolts and bending of rock bolt plates.
 This varied behavior of rock brought new challenges in front of the team. Therefore, such
behavior of rock is regularly and accurately monitored and these problems are encountered by
taking necessary measures using Lining stress controllers (LSC).
3) Sudden collapse of tunnel:
While construction, the tunnel roof of 50m stretch suddenly collapsed and fortunately it didn’t
cause any loss of life. This caused a hindrance in the progress of work.

20.  Various measures were taken to avoid collapse of tunnel like rock bolting after
clearing muck, rock bolting with wire mesh and shotcrete were done
monolithically, continuous monitoring of deformations and deflections, piped
roofing to take high overburden.

21. 3) VENTILATION BUILDING:
 The installation of the ventilation building at South Portal became a very
challenging task as it is located in a landslide region.
 Constructing of the building in a stable deep rock cut, anchoring walls of the
ventilation buildings to arrest movement of building and providing measures
against sliding of slope like anchoring after removing loose cover from the
slope, providing an avalanche gallery.
 Even at the north portal installation of the ventilation building has been
challenging as there is no sufficient space available and must be built along
the slope.
 This slope is in a high avalanche prone area. Finally the building was
constructed in a straight alignment along the tunnel on a raft foundation in a
safe zone devoid from avalanche.

23. 4) ALIGNMENT PRECISION WHILE PROGRESSING:
 Construction of the tunnel was carried out from two ends simultaneously.
Electronic total station survey instruments were used for the purpose of
alignment of tunnel.
 Due to their magnetic nature, they were getting affected because of huge
support installations made of steel as the tunneling is being progressed. Inertial
precision technology (gyro-meters) is used to counter after every one km of
excavation.
5) TRANSPORTATION:
 Transportation availability to the site is not a smooth process in this young
Himalayan region.
 Many challenges are faced during material transportation and this somewhat
added to the delay in work execution.

24. 6) EXTREME WEATHER:
 Rohtang valley region remains inaccessible due to heavy snowfall nearly 6
months; as a result construction work can be carried out only for 6 months in one
year. Therefore the project implementation got hindered and delayed.
 Due to extreme cold conditions at site workers were also having bad effects on
health. Medical aid is provided accordingly.
7) COMMUNICATION ISSUE:
 Due to remoteness of the site and extreme weather conditions like snowfall no
proper network is available and wireless communication through radio is not
possible.
 So installing cables is the only option which is done with the help of BSNL.

25. 8) EXCESSIVE SNOWFALL:
 The tunnel project site faces excessive snowfall in the winters and experiences
subzero temperatures accompanied by frequent avalanches.
 North Portal as such remains closed throughout the winters almost 6 months.

26. SAFETY MEASURES IN TUNNEL
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 Meters for
Emergency communication.
 Fire hydrant mechanisms at every 60 meters.
 Auto incident detection system with CCTV
 cameras at every 250 Meters.
 Air quality monitoring at every 1 Km.
 Evacuation lighting / exit signs at every 25
Meters.
 Broadcasting system throughout the tunnel.
 Fire rated Dampers at every 50 Meters.
 Cameras at every 60 Meters.

29. REFRENCES
 INTERNATIONAL JOURNAL OF INNOVATIONS IN ENGINEERING
RESEARCH AND TECHNOLOGY [IJIERT] ISSN: 2394-3696 Website:
ijiert.org VOLUME 8, ISSUE 8, Aug. -2021.
 Compendium on Atal Tunnel issued by Border Road Organisation.
 https://www.encardio.com/blog/rohtang-pass-tunnel-case-study-geotechnical-
monitoring-instrumentation/
 http://testcf.constrofacilitator.com/the-atal-rohtang-tunnel-a-look-into-the-
construction-marvel/
 https://www.slideshare.net/Bimenpreet/atal-rohtang-tunnel-construction-
process-challenges-and-features

30. THANK YOU