Atal Tunnel

                                                 

Atal Tunnel which is previously known as Rohtang Tunnel, named after India's Former Prime Minister "Atal
Bihari Vapayee" is a highway tunnel being built under the Rohtang pass in the eastern Pir Panajal range if the Himalayas on the Leh-Manali Highway.
It is the longest tunnel in India 8.8 km(5.5 mi) and It is reducing the distance between "Manali and Keylong" bu about 46 km(28.6 mi).

The excavation of the tunnel completed in October 2017 when the blasting from south and north ends joined, and the completed tunnel will open in June 2020.

                                

Map of Atal Tunnel

Note:- The Cabinet had approved ₹6,000 crore for the Atal Bhujal Yojana for five years from 2020-21. Mr. Javadekar said half the cost would be borne by the Center and the rest would be met with a World Bank loan. 

A 3,000-member team of contractual workers and 650 regular employees of the Border Roads Organisation (BRO) have been working in shifts through 24 hours on the Rohtang Tunnel project.

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). 

Short Movie On Atal Tunnel 🔽🔽

                            

Challenges:-

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.

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 cloud-burst and flash flood on 8 August 2003 killed 42 labourers who were building the temporary access road. Questions were also raised on the impact of cutting down more than 700 trees on the ecology.

Some other important facts about Atal Tunnel:-

1. When completed, the 8.8 km (5.5 mi) long tunnel is also set to become the world longest tunnel at an altitude above 3,000 m or 10,000 ft.

2. The nearest in comparison to the Rohtang Tunnel would be the Anzob Tunnel in Tajikistan (length 5 km (3.1 mi), altitude 3,372 metres (11,063 ft)), Salang Tunnel in the Hindu Kush mountains in Afghanistan (length 2.6 km, altitude 3,400m) and the Eisonhower-Johnson Memorial Tunne in the United States (length 2.73 km (1.7 mi), altitude 3,401 m (11,158 ft)).

3. The 85 km distance from Manali to Keylong on the other side of Rohtang Pass is usually covered by vehicles in about five to six hours, without counting the long hours of traffic jams on the hilly route. The same distance would now be covered in less than half-an-hour through the tunnel and without traffic snarls. Keylong would be just 25 km from the South Portal of the tunnel.

Specification about Atal Tunnel:-

➯Telephone at every 150 metres

➯Fire hydrant at every 60 metres

➯Emergency exit at every 500 metres

➯Turning cavern at every 2.2. km

➯Air Quality monitoring every 1 km

➯Broadcasting system

➯Automatic incident detection system with CCTV every 250 metres

➯Width of carriageway: 10.50 metres including one metres footpath on both sides

➯Maximum speed limit: 80 km per hour

➯Max Traffic expected: 3,000 petrol cars a day and 1,500 trucks a day

Direct Info about Atal Tunnel  ↓↓↓

Length of Tunnel	:	8.8 km
Shape of Tunnel	:	Horse Shoe shape. Finished width 10.00 m at road level. (8.00 m pavement and 1.00 m footpath on both the sides)
General altitude of the tunnel	:	It lies between 3000-3100 m altitude
Design speed	:	80 km/h
Temperature variation in the area	:	25-300 C during May-June -200 C to -20 C during Dec-Jan
Construction technique proposed	:	Drill & Blast with NATM
Tunnel ventilation	:	Semi transverse system of ventilation system has been proposed. Following parameters have been taken in design:-
		(a)	Upper tolerance limit for concentration		-	150ppm
		(b)	Visibility factor		-	0.009/m
			(i)	Cars	-	3000 Nos
			(ii)	Trucks	-	1500 Nos
		(d)	Peak hour traffic		-	337.50PCUs
		(e)	Design vehicular speed in Tunnel
			(i)	Maximum Speed	-	80 km/ph
			(ii)	Minimum Speed	-	30 km/ph