chanani nashri tunnal

The Chenani-Nashri tunnel comprises two tubes that run parallel to each other — the main traffic tunnel of diameter 13 m and a separate safety or escape tunnel of diameter 6 m alongside. The two tubes — each approximately 9 km long — are connected by 29 cross passages at regular intervals of every 300 meters along the entire length of the tunnel. These passages add up to about 1 km of tunnel length, and the main and escape tubes, plus the cross passages make up about 19 km of tunnel length. Since such a long tunnel could present the problem of a lack of oxygen, to ensure that there is no excessive carbon-dioxide build-up inside, there are several exhaust meters that will check the air all through the length of the tunnel. With inlets, every 8 meters, bringing fresh air into the main tube, and exhaust outlets every 100 m opening into the escape tube, the tunnel is the country’s first — and the world’s sixth — road tunnel with a transverse ventilation system. Transverse ventilation will keep tailpipe smoke inside the tunnel at a minimum level in order to prevent suffocation and keep visibility at acceptable levels, especially since the tunnel is so long. The 29 cross passages between the two tunnels will be used to evacuate, through the escape tunnel, a user who might be in distress or to tow away any vehicle that might have broken down in the main tunnel. A total of 124 cameras and a linear heat detection system inside the tunnel will alert the Integrated Tunnel Control Room (ITCR) located outside the tunnel to the need for intervention. In the case of a traffic violation, the Control Room informs the traffic police deployed outside the tunnel, who shall impose a fine on errant drivers on the spot.

SOS boxes installed every 150 m will act as emergency hotlines for commuters in distress. To connect to the ITCR to seek help, one would only need to open the door of the SOS box and say ‘Hello’, said an executive of the project. Commuters can use their mobile phones inside the tunnel. To prevent diminution of vision as a result of change in the light while going in or coming out of the tunnel, the lighting inside has been adjusted at a gradient of luminous strength. The tunnel is built with fire safety measures. As soon as sensors detect fire, a safety protocol will kick in, and the pushing of fresh air will stop and only exhausts will function. Longitudinal exhaust fans installed at regular intervals will concentrate on 300 m on either side of the fire, pushing the smoke upward. Ambulances or vehicles carrying foam will rush through the escape tunnel to evacuate commuters and fight the fire.

The heat detection system inside the tunnel will record rises in temperature in the tunnel — the result of excessive emissions which may be caused by one or more vehicles. In such cases, the ITCR will get in touch with staff inside the tunnel, and the offending vehicle will be pulled over into a lay-by and subsequently removed by a crane through the parallel escape tunnel.

The tunnel is located at an altitude of nearly 4,000 feet in difficult Himalayan terrain. Despite having been excavated in such geographic conditions, both tubes are completely waterproof.

Because of this two-lane tunnel, the distance between Chenani and Nashri and hence between Jammu and Srinagar is reduced by 30 km and travel time is cut by two hours. The tunnel bypasses 44 avalanche and landslide-prone spots on the highway. It is an "all-weather" tunnel and enables an increase in trade and tourism in the state. The tunnel also has parking spots in case of vehicle breakdowns.