Making of India's longest rail tunnel: When project looked jeopardised
Uttarakhand), The completion of India's longest rail tunnel between Devprayag and Janasu in Uttarakhand faced significant challenges, including moments when it seemed the tunnel might collapse and jeopardise the whole project, Larsen & Toubro Limited said on Saturday.
"The tunnel boring machine named 'Shakti' was about five km inside the tunnel when it encountered a gush of water from all directions at the rate of around 1,500 litres per minute," Rakesh Arora, Project Director of the tunnel, told PTI.
"Besides the TBM operator, there were 200 people inside the tunnel at that time. It was one of the toughest moments when the tunnel was at risk of flooding or collapsing," he said.
Arora said the situation did not improve for around a month. His team struggled to overcome it by using a combination of chemical as well as cement grouting to stabilise the rings and surrounding rock, consequent to which, the water flow started reducing and the engineers could stabilise the interiors successfully, he added.
"Besides, there were occasions when huge pressure from the surrounding soft rock posed a serious risk to the tunnel's progress, which was successfully handled by speeding up the excavation works with a combination of lubricating the TBM shield using bentonite," Arora added.
The 14.57-km tunnel on the 125-km Rishikesh-Karnaprayag Rail Link Project achieved a breakthrough on April 16 in the presence of Railway Minister Ashwini Vaishnaw, Uttarakhand Chief Minister Pushkar Singh Dhami and other railway and state officials.
Devprayag-Janasu tunnel, besides being the longest, was completed with the fastest speed in the world. It was for the first time that a Single Shield Hard Rock TBM of 9.11-metre diameter was used in the Himalayas to excavate the mountains.
According to the Rail Vikas Nigam Limited , out of 14.57 km, 10.49 km was completed through TBM and the rest with the traditional drill and blast method.
"The 9.69-metre diameter Cabrera tunnel in Spain was built by a Double Shield Tunnel Boring Machine at an average rate of 423 metres per month and the 10.49-km Devprayag-Janasu tunnel has been completed by Single Shield TBM at an average rate of 413 metres per month, becoming the second fastest in the world,' RVNL Chairman and Managing Director Pradeep Gaur had told PTI on the day breakthrough was achieved.
"As the Himalayas are the most challenging geologically, it makes the whole project extremely demanding and interesting. Out of a total of 125 km, 105 km pass through the tunnels.
"Around three km are covered through bridges and four km by adits and cross passages; the left portion is just 12 to 13 km which consists of 12 station yards," Gaur added.
Arora said the TBM's biggest enemies are water ingress and soft squeezing rock which try to obstruct them from digging a tunnel in the Himalayas. Once a TBM is stuck inside a tunnel, the project is abandoned, he added.
According to L&T officials, besides the state-of-the-art TBM machine, multiple scientific and physical investigations helped them ascertain what kind of rocks they would get ahead and they made preparations accordingly.
"There is a manual probe through drilling and studying the speed of drilling to find out the rock conditions up to 60 metres ahead. Hard rock gives us slow penetration while soft rocks make penetration faster," Arora said.
"The scientific method is Tunnel Seismic Prediction in which seismic waves are emitted and a report is prepared on the condition of rocks ahead by studying the speed of the waves. TSP tells us what kind of rock is 100 metres ahead of TBM and 15 metres on both sides of TBM," he said.
The construction firm said they used another physical method to know the rock conditions by investigating the excavated muck.
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Hindustan Times
4 hours ago
- Hindustan Times
DP 2034 to be modified in order to facilitate land acquisition for coastal road
MUMBAI: After a diktat by chief minister Devendra Fadnavis, the Development Plan (DP) department of the BMC on Saturday issued a notice to modify the DP 2034 to make a provision for a coastal road from Versova to Dahisar. The stretches from Versova to Dahisar and Dahisar to Bhayandar are being carried out by the BMC. Mumbai: Maharashtra Chief Minister Devendra Fadnavis speaks during the two-day National Conference of Estimates Committees of Parliament and State/UT Legislative Bodies, at Vidhan Bhavan, in Mumbai, Monday, June 23, 2025. (PTI Photo/Shashank Parade)(PTI06_23_2025_000115A) (PTI) On Friday, when Fadnavis took a review of the coastal road, officers implementing the project said that land acquisition would be difficult if the areas were not marked. Since the government wants the BMC to start the work in August 2025, it asked for immediate changes to the DP. 'The CM told us to issue the notice immediately,' said a senior officer of the DP department. Once the reservation is changed, acquisition will become easier, said officers. Accordingly, some plots in Pahadi village, Goregaon, and others in Borivali, Eksar and Dahisar will be now reserved for the coastal road. The project will require 164 hectares of land—of this 61.5% is BMC land, 10% belongs to the state government while the rest is private land. Fadnavis has asked the collectors of Mumbai Suburban and Thane district to give advance possession of the government land required for the project so that construction can start. One MHADA layout at Aram Nagar and one building of the Central Institute of Fisheries Education, both in Andheri, will have to be acquired for this. The BMC will have to kill a large number of mangroves, and the compensatory afforestation will be done in Chandrapur district. The Maharashtra Coastal Zone Management Authority has already given clearance to the project, but the Forest Right Committee of the Mumbai suburban district is yet to do so. This committee, formed to protect the rights of forest dwellers under the Scheduled Tribes and Other Traditional Forest Dwellers (Recognition of Forest Rights) Act, 2006 , plays a role in cases where forest land is proposed for diversion for non-forest purposes. The work between Versova and Dahisar will be done in six phases while the Dahisar-Bhayandar road construction will be a separate one. The alignment of the road is still to be finalised on the DP. The chief minister has ordered work on the coastal road to begin by August 2025 and mandated that the Versova-Dahisar stretch be completed by December 2028. The entire project will cost ₹ 22,000 crore.
Time of India
15 hours ago
- Time of India
Agroforestry push: Centre issues model rules to ease tree felling on farmland, boost legal timber trade
In a step to promote agroforestry and streamline tree felling norms on agricultural lands, the Centre has notified a new set of model rules aimed at easing procedural hurdles for farmers, increasing tree cover outside forests, and supporting India's climate goals under the Paris Agreement. In a letter dated June 19 to all state governments, the environment ministry said the 'Model Rules for Felling of Trees in Agricultural Lands' are designed to simplify tree-felling permissions, improve traceability, and enable farmers to integrate trees into farming systems without complex red tape, PTI reported. The initiative, the ministry said, supports India's broader efforts to double farmer incomes, reduce timber imports, and build sustainable land-use models. A key challenge so far has been the absence of harmonised rules across states—creating bottlenecks in tree cultivation and marketing of agroforestry products. Under the new framework, the State Level Committee (SLC)—earlier constituted under the Wood-Based Industries (Establishment and Regulation) Guidelines, 2016—will also oversee the agroforestry framework. The committee will now include officials from revenue and agriculture departments, and will empanel agencies for on-ground verification of plantations and timber transit. Farmers will be required to register their land on the National Timber Management System (NTMS) portal, entering details such as land ownership, plantation data (species, sapling count, planting date), and tree height. Live Events For plots with over 10 trees, applicants must file online with detailed tree information. Verifying agencies will inspect the land, submit a report, and based on the data, a felling permit will be generated. In cases involving 10 or fewer trees, uploading photographs of the trees and later the stumps will suffice, with the system estimating yield and species using AI tools. Officers may verify these as needed, but no objection certificates (NOCs) will be auto-generated via NTMS, according to PTI. Divisional forest officers will monitor verifying agencies and submit quarterly reports on their performance to the SLC. Currently, states follow their own regulations regarding tree felling on farmland. Some exempt specific species from permissions, while others require felling clearance even on private land depending on the location and tree type. The NTMS system aims to solve a core issue for farmers—lack of recognised proof that the timber is legally harvested. This often results in lower prices and barriers to market access, especially from wood-based industries and exporters wary of sourcing from unverified supply chains. By offering a digital trail of compliance, the NTMS is expected to unlock better prices for farmers, especially in the context of the EU Deforestation Regulation, which mandates that timber imports into the EU must not be linked to deforestation after 2020. The ministry said the new framework will make agroforestry more structured, transparent, and remunerative, helping build a legal and export-ready ecosystem for Indian timber.
Time of India
16 hours ago
- Time of India
Agroforestry push: Centre issues model rules to ease tree felling on farmland, boost legal timber trade
In a step to promote agroforestry and streamline tree felling norms on agricultural lands, the Centre has notified a new set of model rules aimed at easing procedural hurdles for farmers, increasing tree cover outside forests, and supporting India's climate goals under the Paris Agreement. Tired of too many ads? go ad free now In a letter dated June 19 to all state governments, the environment ministry said the 'Model Rules for Felling of Trees in Agricultural Lands' are designed to simplify tree-felling permissions, improve traceability, and enable farmers to integrate trees into farming systems without complex red tape, PTI reported. The initiative, the ministry said, supports India's broader efforts to double farmer incomes, reduce timber imports, and build sustainable land-use models. A key challenge so far has been the absence of harmonised rules across states—creating bottlenecks in tree cultivation and marketing of agroforestry products. Under the new framework, the State Level Committee (SLC)—earlier constituted under the Wood-Based Industries (Establishment and Regulation) Guidelines, 2016—will also oversee the agroforestry framework. The committee will now include officials from revenue and agriculture departments, and will empanel agencies for on-ground verification of plantations and timber transit. Farmers will be required to register their land on the National Timber Management System (NTMS) portal, entering details such as land ownership, plantation data (species, sapling count, planting date), and tree height. For plots with over 10 trees, applicants must file online with detailed tree information. Verifying agencies will inspect the land, submit a report, and based on the data, a felling permit will be generated. Tired of too many ads? go ad free now In cases involving 10 or fewer trees, uploading photographs of the trees and later the stumps will suffice, with the system estimating yield and species using AI tools. Officers may verify these as needed, but no objection certificates (NOCs) will be auto-generated via NTMS, according to PTI. Divisional forest officers will monitor verifying agencies and submit quarterly reports on their performance to the SLC. Currently, states follow their own regulations regarding tree felling on farmland. Some exempt specific species from permissions, while others require felling clearance even on private land depending on the location and tree type. The NTMS system aims to solve a core issue for farmers—lack of recognised proof that the timber is legally harvested. This often results in lower prices and barriers to market access, especially from wood-based industries and exporters wary of sourcing from unverified supply chains. By offering a digital trail of compliance, the NTMS is expected to unlock better prices for farmers, especially in the context of the EU Deforestation Regulation, which mandates that timber imports into the EU must not be linked to deforestation after 2020. The ministry said the new framework will make agroforestry more structured, transparent, and remunerative, helping build a legal and export-ready ecosystem for Indian timber.
