Tunnel construction in the country has picked up pace over the past few years due to an increased focus on infrastructure development. Sectors such as railways, roads, hydropower, water supply and metro rail offer ample opportunities to contractors. The growth of tunnelling activity is largely driven by big-ticket projects. Of late, the size of tunnelling projects has witnessed a substantial increase.
With regard to construction methods, advanced technologies such as those using tunnel boring machines (TBMs) and the new Austrian tunnelling method (NATM) are being used extensively for tunnelling in congested urban areas. Excavation using TBMs has been quite successful in constructing metro, water supply and sewerage tunnels. Sector-wise, TBMs are the most widely used for tunnels in urban rail and water supply and sewerage projects in congested urban areas. With regard to the irrigation sector, TBMs are slowly replacing the drill-and-blast method (DBM) of construction that was used earlier. In the water supply and sewerage sector, too, the use of TBMs for tunnelling has started recently, primarily in urban areas.
Indian Infrastructure reviews the existing project portfolio in the road, hydropower, railway, metro rail, and irrigation, water supply and sewerage sectors, and highlights the upcoming opportunities for tunnelling contractors…
Road tunnels
India Infrastructure Research tracked 70 upcoming projects in the roads and highways sector with a combined length of 358.05 km across the country. The total upcoming investment for the excavation of tunnels in the roads and highways sector is around Rs 514.05 billion. A state-wise analysis indicates that Jammu & Kashmir has the maximum share in the total upcoming tunnel length at 155.25 km. It is followed by Rajasthan and Maharashtra, with an upcoming tunnel length of 59.62 km and 40.63 km respectively.
Some of the key upcoming projects in the sector are the Bhenda Hera-Moondiya eight-lane tunnel project in Rajasthan, the Chowkibal-Chamkot highway tunnel project (Sadhana Pass) in Jammu & Kashmir, the Shiradi Ghat tunnel road bypass project in Karnataka and the twin tunnel for the Goregaon-Mulund link road project.
The upcoming tunnel length in the sector is expected to create a huge demand for equipment used in DBM, TBMs, drillers, excavators, loaders, cranes, etc. Various opportunities are expected to be created for TBM suppliers such as Herrenknecht, Hitachi Zosen, JCB, Caterpillar, Robbins, Hyundai Construction and Atlas Copco.
Growth in the sector is being driven by the launch of the Bharatmala programme, the Pradhan Mantri Gram Sadak Yojana, Setu Bharatam and Char Dham connectivity, as well as the development of economic corridors.
Hydropower tunnels
India infrastructure Research tracked 639 upcoming tunnels in the hydropower sector with a total length of 1,037.05 km. State-wise, Arunachal Pradesh has the maximum share of upcoming tunnel length in the sector at 394.74 km, followed by Himachal Pradesh and Uttarakhand with upcoming tunnel lengths of 154.51 km and 139.61 km respectively.
Some of the key upcoming projects in the sector are the Lower Sileru project in Andhra Pradesh, the Upper Siang I project in Arunachal Pradesh, the Devsari project in Uttarakhand and the Luhri project in Himachal Pradesh. The majority of the upcoming tunnels in the hydropower sector will have a horseshoe shape.
In the hydropower sector, DBM is the most commonly used tunnelling method. Faster and highly advanced/mechanised technologies such as TBMs are also slowly gaining traction. Further, NATM is being used extensively for tunnel excavation in the sector after its successful implementation in the Uri hydro tunnel. The sector has also seen the emergence of new trends such as the use of steel fibres in shotcrete, self-drilling anchor bolts, and adoption of PU grout, pipe roofing and pre-grouting techniques. Hence, the upcoming projects in the sector will open up a lot of opportunities for manufacturers of the aforementioned material and equipment.
Railway tunnels
In the railway sector, around 111 upcoming tunnels have been tracked with a total length of 74.96 km. Meghalaya has the maximum upcoming tunnel length in the sector with 39.06 km. It is followed by Maharashtra, with an upcoming length of 19.9 km.
Some of the key upcoming projects in the railway sector involving excavation of tunnels are the Bilaspur-Mandi-Lehnew line project in Jammu & Kashmir, the Byrnihat-Shillong new line project in Meghalaya, the Kanhangad-Kaniyurnew rail line project in Kerala and the Roha-Dighi port-rail connectivity project in Maharashtra.
The selection of the tunnel excavation method in the railway sector depends on factors such as geological conditions, the cross-sectional area and the shape of the tunnel, the length of the tunnel, vibration restrictions and allowable ground settlements. While DBM has been the dominant method of tunnel excavation in the railway sector in India, mechanised tunnelling methods such NATM and TBM have also gained traction recently. In terms of length, around 42.25 per cent of completed, ongoing and planned railway tunnels have adopted the NATM. With a large pipeline of railway projects planned for implementation, NATM is expected to pick up pace going forward.
Metro rail tunnels
In the metro rail segment, around 96 upcoming projects have been tracked with an underground length of 154.59 km, along with about 72 underground stations. Maharashtra has the highest number of upcoming metro rail tunnel projects in the country at 22, while Delhi has the highest upcoming underground length in the metro rail sector at 49.65 km.
Some of the key upcoming projects for the excavation of tunnels in the metro rail sector are the Delhi-Gurugram-SNB regional rapid transit corridor Phase I in Delhi and Rajasthan, the Bengaluru metro rail project Phase III in Karnataka, the Guwahati metro rail project Phase I in Assam, the Mumbai metro rail project in Maharashtra and the Lucknow metro rail project in Uttar Pradesh.
Metro rail tunnelling is a recent phenomenon that started with the development of public mass transport systems in dense cities. Around 10 per cent of the upcoming length of metro rail projects is underground. The metro rail sector has extensively deployed TBMs in the past few years to undertake tunnelling works. Currently, tunnels spanning a length of at least 126 km in the sector are under construction and are using the TBM technology to a certain extent. Most of the upcoming metro rail projects will deploy TBMs, thereby creating opportunities for TBM manufacturers.
Irrigation, water supply and sewerage tunnels
In the irrigation, water supply and sewerage sectors, a total of 49 upcoming tunnels with a length of 990.97 km have been tracked. Maharashtra has the maximum upcoming tunnel length in the sector at 765.56 km. Some of the key upcoming projects in the sector are the Gargai-Modak Sagar tunnel in Maharashtra, a new tunnel under the Kaleshwaram irrigation project in Telangana, and the Par-Tapi-Narmada link project in Maharashtra.
In the irrigation, water supply and sewerage sectors, both mechanised methods such as the TBM method and conventional methods such as DBM are being used for the excavation of tunnels. Of the total number of tunnel projects being constructed/completed using TBM, over 66.67 per cent and 16.67 per cent have used the double-shielded TBM and earth pressure balance TBM respectively, in the irrigation sector. Going forward, these technically sophisticated TBMs, double-shielded TBMs, are expected to dominate the irrigation tunnelling segment.
The road ahead
The scope of tunnel construction in the country has widened with the increased focus on infrastructure development. Metro rail tunnels and hydropower tunnels will continue to be the biggest demand drivers of modern tunnelling equipment and technologies.
Going forward, Indian and foreign joint ventures are expected to bid for the excavation of tunnels and more players are expected to enter the market.