Tunnelling has become an integral part of India’s infrastructure development with many underground projects coming up in transportation, hydropower and water projects. Construction Times explores the emerging trends, major challenges and new opportunities in tunnelling.
The infrastructure development has gone deep under as tunnelling has become a major focus in the Indian construction industry. Tunnels are crucial for reducing travel time, improving safety, and enhancing economic activity. These tunnels help bypass difficult terrains, provide access to remote regions, and facilitate urban decongestion through metro and road tunnels. Many underground projects and projects in the mountainous regions being developed. The country has witnessed development of a range of underground metro projects, road and railway tunnels and water pipeline projects in the recent past.
Enhancing connectivity
Tunnels are lifelines that traverse vast distances, cutting through mountains and beneath the earth to ensure uninterrupted connectivity. They offer reliable, year-round access, ensuring consistent connectivity in mountainous regions which are prone to extreme weather conditions that can affect transportation. In strategically important areas, tunnels provide secure and efficient transportation routes for both military and civilian purposes. In cities, metro and road tunnels ease congestion and support sustainable urban mobility. Underground tunnels, especially for metro rail systems, offer alternative transportation routes, alleviating surface traffic congestion and enhancing urban mobility. By integrating advanced engineering techniques, these tunnels strengthen national infrastructure, foster economic growth, and improve resilience against natural disruptions like landslides and heavy snowfall. Tunnelling also reduces pollution which is a big menace these days.
The market dynamics
The development of road and railway tunnel projects in India is progressing rapidly, driven by government initiatives like the Bharatmala and Rail Vikas programs. India has seen many tunnel projects coming up in the recent past. The country is home to some of the iconic tunnel projects in the world. These include the Zojila Tunnel in Jammu & Kashmir, Atal Tunnel in Himachal Pradesh and Sela Pass Tunnel in Arunachal Pradesh that are enhancing connectivity in challenging terrains. The Indian Railways is also advancing tunnel construction, notably in the Northeast and Himalayan regions, to improve freight and passenger transport. The metro rail infrastructure has seen many underground projects coming up across the country where tunneling played the significant role in establishing the network. The Kolkata Metro rail has established the country’s first underwater metro rail network on the East-west metro corridor of Kolkata. The upcoming Mumbai-Ahmedabad high-speed rail connectivity project has seen one of the most challenging underground tunneling activity in Mumbai. Apart from these, many tunnel projects are underway across the country while many are planned in transportation, irrigation and water pipelines.
With increased investment in road and railway tunnels, as well as metro and urban underground spaces, the total length of tunnels in India has seen substantial growth. According to R K Dhiman, AVSM VSM, Former ADG, BRO and President, Tunnelling Association of India (TAI), currently, India has over 2,500 km of tunnels constructed or under development, covering national highways, railway corridors, metro and hydropower systems. According to Union Minister Nitin Gadkari, NHAI has completed 35 tunnel projects of 49 km in length costing Rs 20,000 crore.
Tech advancements
Tunnelling has gained more traction in the country with the introduction of newer methods and technologies. According to Dr Nalin Gupta, Managing Director, J Kumar Infraprojects Ltd, traditional methods like drill-and-blast are now complemented by advanced techniques such as the New Austrian Tunneling Method (NATM) and Tunnel Boring Machines (TBMs). “TBMs, in particular, have revolutionized tunneling by enabling precision excavation with minimal environmental impact. These machines can handle diverse geological conditions, reducing project timelines and improving safety. Innovations like automated monitoring systems, digital twin technology, and AI-driven geological mapping further enhance efficiency. Additionally, advancements in ground reinforcement, ventilation, and waterproofing are improving tunnel durability, ensuring long-term sustainability and resilience in challenging environments,” he adds.
In TBM tunnelling projects, key technologies utilized include shield tunnelling, automated TBMs, data management systems, embedded cameras, continuous belt conveyors, complex grouting processes for segment sealing, laser guidance, computerized control systems, and specialized shield machines depending on the soil conditions, all aimed at efficient excavation and minimizing disruption to the surrounding environment.
Rahul Agarwal, Chief Financial Officer, Patel Engineering Ltd, adds, “Beyond TBMs, tunnelling has greatly benefited from Building Information Modelling (BIM) and digital twin technology, which streamline project execution. BIM allows improved coordination and visualization between construction and design teams. On the other hand, digital twin technology provides real-time monitoring of tunnelling equipment, using predictive analytics to prevent mechanical failures and optimize maintenance schedules. These technologies support long-term infrastructure resilience through the assurance that modern tunnels are not only built faster but also with greater precision, sustainability, and endurance.”
While the country is still adopting new materials and techniques, there is a growing interest in advanced materials like Glass Fiber Reinforced Polymer (GFRP) to enhance durability, efficiency, and sustainability, particularly in challenging environmental conditions. Papiya Saha, Business Development, Dextra India, elaborates, “Dextra offers a comprehensive suite of advanced solutions for tunnel projects, including high-performance GFRP-based products such as rock bolts, reinforced rebar, and anchors. These GFRP solutions are specifically engineered to deliver exceptional corrosion resistance and long-term durability in demanding underground environments.”
Tunnelling – a challenging task
Tunneling projects face several major challenges, including geological uncertainties, water ingress, high overburden pressure, and environmental concerns. Unstable rock formations, seismic activity, and soft soils can lead to collapses or construction delays. Additionally, urban tunneling poses risks to existing infrastructure, while tunnels in hilly terrains must overcome extreme weather conditions. According to Agarwal, stability at excavation is a must, with ongoing monitoring and reinforcement to prevent collapse and deformation. These challenges need to be overcome with precision engineering and advanced technology to ensure seamless implementation.
Dr Gupta elaborates, “To minimize these challenges, advanced techniques like geotechnical investigations, real-time monitoring, and predictive analytics are used. TBMs help navigate difficult geology efficiently. Ground freezing, shotcrete lining, and rock bolting strengthen tunnel stability. Environmental impact assessments and sustainable construction practices ensure minimal ecological disruption, making tunneling safer and more efficient.”
According to Raman Kapil, President & COO - Buildings & Infrastructure, Tata Projects, key challenges are faced while working at congested area, diversion of underground utilities and transit lines, and risk of water seepage. To mitigate the risk of water seepage, “it is essential to conduct a hydrogeological assessment prior to tunnel construction, implement groundwater control measures such as dewatering, grouting, and the use of waterproofing membranes, incorporate appropriate drainage systems, sealing materials, and waterproofing methods to minimize water ingress, and construct TBM confinement at the launching shaft to reduce flooding risk,” he asserts.
The recent tunnel collapse incident at the Srisailam Left Bank Canal (SLBC) tunnel in Telangana is an eye opener towards the need for a more aggressive approach towards averting such unfortunate incidents in future.
Dhiman elaborates, “Safety during construction and operation of tunnel is a priority. We advocate for advanced safety protocols, including remote monitoring systems, predictive modelling and real-time ventilation control, enhanced training for workers, especially in confined space safety. Innovations such as IoT-based sensors to monitor structural integrity, automated early-warning systems, and worker-tracking devices have been crucial in reducing incidents. Encouraging a safety-first culture and ensuring adherence to international safety standards remain our top priorities.”
Opportunities galore!
The tunnelling sector in India is poised for significant growth, driven by the increasing demand for efficient transportation networks, urban expansion and water infrastructure projects. “With initiatives like the Gati Shakti National Master Plan and rising private sector participation, we expect tunnelling activities to expand rapidly,” observes Dhiman.
According to Union Minister Nitin Gadkari, 75 highway tunnel projects worth Rs 49,000 crore totalling 146 km are currently under construction in India while an additional 78 tunnel projects costing Rs 1.10 lakh crore spanning 285 km are also planned. These numbers reveal a huge opportunity for contractors and other stakeholders of the industry.
Looking at the emerging opportunities, Agarwal states, “At Patel Engineering, we believe that now is an opportunity for utilising innovative technology and sophisticated geotechnical designs to drive innovation in challenging tunnelling projects.”
As the tunnelling sector in India is poised for significant growth, Dhiman highlights the need for a proactive approach. “Government policies heavily influence project timelines, costs, and environmental considerations in tunnelling. Keeping in view of potential of tunnel work in India, we should have a Centre for Tunnelling for overall development of all types of tunnels with a special focus of safety protocols using different methodologies of tunnel construction. Considering the huge potential for tunnel works ahead, a proposal for early installation of TBM factory along with rich support system to reduce downtime of procurement from overseas, need to be explored in the country.”
As India’s infrastructure development is gaining steam, underground projects will play a crucial role in the future infrastructure development of the country and tunnelling will be the way forward to achieve the goals.
