Tunnel development in the country is driven by investments in the hydropower, railway, roads and highways, metro rail, and water and sewerage sectors. While the railway sector was the first to undertake tunnel development, the maximum number of tunnels have been developed in the hydropower sector. Tunnels for the supply of water received a boost with the launch of large programmes such as the Jawaharlal Nehru National Urban Renewal Mission, the Pradhan Mantri Krishi Sinchayee Yojana and the Interlinking of Rivers programme for the exploitation of water resources. The roads and highways sector has witnessed limited tunnel construction, though some has taken place in hilly regions. Metro rail tunnelling is a recent phenomenon and has been spurred by the decision of dense cities to develop efficient public transport systems.
Given that the Indian industry is just beginning to use modern technology for tunnel construction, almost all the upcoming tunnel projects are of much higher value than had been the case in the past. There is also greater room for the adoption of international standards in tunnel design and construction. Rising investments in tunnel construction have resulted in high growth in the tunnel equipment market as well. Going forward, as the pressure on land increases (with land being required for other productive eco-
nomic and social uses) there will be greater need to construct underground structures in the metro, water and sewerage, and road sectors.
Projects with record-breaking tunnel lengths have been constructed or initiated
India Infrastructure Research analysed over 1,628 tunnels spread across three stages of development — completed, under construction and awarded. These tunnels span over 3,418 km. In terms of length, 61 per cent of this tunnel length has been completed, 32 per cent is under construction and the remaining 7 per cent has been recently awarded.
The size of tunnelling projects is witnessing a substantial increase. Longer and larger tunnels are beginning to be developed. Although such cases are still few in number, developers have started planning larger-sized projects as they acquire greater confidence in tunnel construction. For instance, Indian Railways is implementing its biggest project so far – the Katra-Qazigund railway line in Jammu & Kashmir – which involves the development of a total tunnel length of 161.55 km. In the water supply segment, the Municipal Corporation of Greater Mumbai awarded the 9.7 km Chembur-Wadala-Parel tunnel which entails an investment of Rs 13.65 billion. In the metro rail segment, Mumbai Metro Rail Corporation Limited awarded the construction of the 33.5 km underground length running along the Colaba-Bandra-Santacruz Electronic Export Processing Zone stretch. The tunnel construction work is estimated to entail a total investment of Rs 181 billion. Under the Parbati Stage II hydroelectric project, a 31.52 km head race tunnel is being constructed. Besides, a single tunnel, 95.4 km in length, is planned to be constructed under the Krishna (Satpewadi)-Nira (Somanathali) link canal project.
Deployment of TBMs increased in urban infrastructure
The metro rail and water and sewerage sectors have extensively deployed tunnel boring machines (TBMs) in the past few years to undertake tunnelling works. In the metro rail segment alone, tunnels spanning a length of at least 209 km are under construction using the TBM technology. Another 40 km of metro tunnel length is planned to be taken up for development using TBMs. The hydro sector has also started experimenting with TBMs. Hydro tunnels totalling a length of 40 km have used or are using this technique. Similarly, in the irrigation and water supply sectors, the technology has been or is being used to construct at least 23 tunnels spanning a total length of 202 km.
Modern equipment industry is dominated by foreign players
Specialised equipment such as TBMs, road headers and shutter systems are supplied by foreign companies such as Herrenknecht (Germany), Robbins (US), Okumura (Japan) and Atlas Copco (Sweden). TBMs are supplied by Herrenknecht, the Hitachi-Zosen joint venture, Okumura, Robbins, Shanghai Tunnel Engineering Company Limited and Seli-Kawasaki, all international players. Other traditional equipment – excavators, loaders, crawler cranes and other types of cranes – are supplied by Indian players as well as foreign players.
Other key trends
Conventional methods of drill and blast, boring, cut and cover, etc. have been the preferred techniques for development of tunnels across sectors, particularly hydropower, railways and roads. New and innovative materials and ancilliary equipment such as geosynthetics, geomembranes, steel anchors and self-drilling rock bolts have been deployed to improve the durability and strength of tunnels.
Further, there is a growing focus on smart/ intelligent tunnels which feature integrated traffic control systems, video surveillance, wireless communication systems, entrance detection control systems, electrical fire signalling systems, SOS call boxes, etc. The Chenani-Nashri tunnel is a case in point.
India’s tunnel sector has continued its growth momentum in the past few years, with several big-ticket and first-of-its-kind projects being completed, launched and announced. In June 2017, the Ministry of Railways laid the foundation stone for the final location survey of the Bilaspur-Manali-Leh new broad gauge line in Jammu & Kashmir. The project involves the construction of a 27 km long tunnel which will house the country’s first railway station inside a tunnel. In its first phase, the railway line will connect 74 tunnels, 124 major bridges and 396 minor bridges. As of October 2018, the final location survey of the 465 km line is under way and considering the difficult terrain, it will take at least two years to complete, after which the project will be sent for approval. In May 2017, the Kolkata Metro Rail Corporation completed the construction of the first-of-its-kind underwater metro rail tunnel below the Hooghly river.
The 502 metre long underwater tunnel was dug by a TBM procured from the Herrenknecht plant located in Schwanau, Germany. The tunnel contractor was Afcons Transtonnelstroy. The 16.6 km long metro line will connect Howrah in the west to Salt Lake in the east in Kolkata city, and will comprise a total of 12 stations. Under the Mumbai Metro Line 3 project too, a part of the Bandra-Kurla Complex (BKC) metro station and a 170 metre section of the tunnel will be constructed under the Mithi river. A 153 metre section of the tunnels at the BKC station, a good part of which will be in the waterbody, is to be built by the New Austrian Tunnelling Method. The project is currently under implementation.
Further, bids have been invited for India’s costliest rail tunnel which is to be constructed under the sea. In April 2019, National High Speed Rail Corporation Limited floated its second high-value tender for the design and construction of India’s first undersea tunnel for the Mumbai-Ahmedabad high speed rail (HSR) corridor. Bids have been invited for this 7 km stretch undersea tunnel that will be constructed under the seabed. The contract value is estimated at Rs 70 billion. The last date for bid submission is August 23, 2019. In all, a 21 km tunnel will be constructed as part of the HSR corridor.
Meanwhile, the government has invited fresh bids for two road tunnel projects due to IL&FS Transportation Networks Limited’s (ITNL) bankruptcy. ITNL had been originally assigned the contracts. The contract for the construction of the 14.2 km Zojila tunnel was reinvited in February 2019 and the last date for bid submission was June 26, 2019. Construction work on the 6.5 km long Z Morh tunnel has been partially completed. The tender for the pending work will be reinvited soon. Earlier, in December 2018, Asia’s longest irrigation tunnel with a total length of 49.8 km (twin tunnels of 24.9 km length) was completed in a record time of nine months. The tunnel was part of the Kaleshwaram lift irrigation project which involves the construction of seven tunnels spanning a total length of 203 km.
The tunnelling industry in India is witnessing high growth and seems poised for changes in technology. With several project awards coming up across sectors, tunnel infrastructure is expected to expand significantly. It is estimated that over Rs 5 trillion worth of projects will be awarded in the next five years. As a result, opportunities for raw material suppliers and equipment providers will increase significantly. With more industry players tying up with international players either for risk assessment, design or construction technology, the industry will witness lower risks in project construction. However, construction and completion challenges faced by most infrastructure projects along with issues such as geological complexities, inadequate investigations, deficiencies in contract documents, poor contracting practices, delayed decision-making, etc. may require greater attention in the near term.