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The completion of India’s longest rail tunnel between Devprayag and Jansu in Uttarakhand faced important challenges, including a moment when it seems that the tunnel can destroy and danger the entire project, Larsen & Toubro Limited (L&T) said on Saturday.
The tunnel project director Rakesh Arora said, “The tunnel boring machine (TBM) was about five km inside the tunnel named ‘Shakti’, when it faced water from all directions at the rate of about 1,500 liters per minute.”
“Apart from the TBM operator, there were 200 people inside the tunnel at the time. It was one of the most difficult moments when the tunnel was in danger of flooding or collapsing. However, we immediately took corrective measures.”
Shri Arora said that the situation did not improve for about a month. He said that his team struggled to remove it by using a combination of chemicals and chemicals to stabilize the chemical and the surrounding rock, as a result, as a result, the flow of water began to decrease and the engineers could successfully stabilize the interiors, he said.
“In addition, there were occasions when heavy pressure from the surrounding surrounding surrounding surrounding the tunnel was presented a serious risk, which was successfully accelerated, which works with a combination of lubricating the TBM shield using Bentonite,” Sri Arora said.
The 14.57 km tunnel on the 125-Cm Rishikesh-Karnaprayag Rail Link Project achieved success in the presence of Railway Minister Ashwini Vaishnav, Uttarakhand Chief Minister Pushkar Singh Dhammi and other railway and state officials on 16 April.
Devprayag-Janasu tunnel, in addition to being the longest, was completed with the fastest speed in the world. This was the first time that a single shield hard rock TBM of 9.11-meters of diameter was used in the Himalayas for the excavation of the mountains.
According to Rail Vikas Nigam Limited (RVNL), out of 14.57 km, 10.49 km was completed with TBM and other traditional drills and blast method.
“9.69-meter Vyas Kabrara Tunnel was built by a double shield tunnel boring machine (TBM) at an average rate of 423 meters per month and a 10.49-km devprayag-janasu tunnel has been completed by single shield TBM at an average rate of 413 meters, which is in a month,” was told to PTI on a day, “was told to the day.
“As the Himalayas are geological most challenging, it makes the entire project extremely demand and interesting. A total of 125 km, 105 km tunnels.
Gaur said, “About three km is covered through bridges and four km (opening) and cross route; the left part is just 12 to 13 km with 12 station yards,” Gaur said.
Shri Arora said that TBM’s largest enemies are water entry and soft squeezing rocks that try to interrupt them to dig a tunnel in the Himalayas. Once a TBM gets stuck inside a tunnel, the project is released, he said.
According to L&T officials, in addition to state -of -the -art TBM machines, many scientists and physical examinations helped them to find out what kind of rocks they would carry forward and they prepared accordingly.
“There is a manual probe through drilling and study the speed of drilling to detect the position of the rock up to 60 meters further. Hard Rock gives us slow penetration, while soft rocks enter rapidly,” said Shri Arora.
“The scientific method is a tunnel seismic prediction (TSP) in which seismic waves are excreted and a report on the condition of the rocks is prepared by studying the speed of the waves. TSP tells us what kind of rock is the rock at a distance of 15 meters on either side of TBM and 15 meters on either side of TBM.”
The construction firm said that he used another physical method to know the condition of the rock by examining the excavated silent.
(Except for the headline, the story has not been edited by NDTV employees and is published by a syndicated feed.)
