India’s infrastructure landscape is evolving with the development of smart and sustainable tunnels that are revolutionising transportation and urban planning. The push for sustainability in tunnelling is driven by the significant environmental impact associated with traditional construction methods, ranging from dust and particulate matter from excavation and drilling to greenhouse gas emissions from high energy consumption and resource-intensive operations.
To address these challenges, there is a growing emphasis on the adoption of energy-efficient practices to minimise the environmental footprint of tunnel construction. Simultaneously, the deployment of advanced technologies is accelerating, driving improvements in construction efficiency, energy optimisation and project timelines.
In line with global best practices, Indian tunnel projects are increasingly integrating high-performance systems such as energy-efficient heating, ventilation and air conditioning (HVAC), robust safety technologies and mature firefighting systems. These systems are essential not only for ensuring the structural integrity of the tunnels but also for enhancing operational and worker safety.
Moreover, advanced waterproofing techniques are gaining traction across Indian tunnel projects to prevent water ingress and bolster tunnel durability, ultimately minimising damage and accidents while ensuring the long-term structural strength of tunnels.
Advanced HVAC systems
The use of advanced HVAC systems is critical for building smart tunnels, especially for roads and underground metro projects. These systems are designed to ensure a safe environment by providing effective ventilation through temperature control and air quality management. These systems are also essential for ensuring the safety of passengers in case of emergencies like fire hazards and aid in reducing energy consumption. The different types of equipment used for ventilation in tunnels include jet fans, dampers, axial fans, and supervisory control and data acquisition (SCADA). The use of jet fans and dampers helps to remove smoke, pollutants, etc., from the airflow, while axial fans aid in maintaining air quality and circulation. Further, the deployment of SCADA enables the continuous monitoring and automated control of airflow systems in tunnels. These advanced systems regulate ventilation fans, swiftly identify potential hazards, and support rapid emergency response measures, ensuring that the tunnel environment remains safe and efficient.
Moreover, with the rising impetus on sustainability, energy efficiency and reduced emissions, sustainable innovations are being increasingly explored. Some key innovations include the use of variable frequency drives that optimise fan speeds based on real-time air quality and reduce energy consumption. Heat recovery systems that capture and reuse heat generated for various purposes help improve efficiency and reduce operational costs of tunnel ventilation systems.
Further, tunnel ventilation shafts are being used across various tunnel projects. These are vertical passages that help remove stale air from underground tunnels and are crucial for maintaining air quality, controlling temperature and managing smoke in case of fire. These have been deployed in the Zojila tunnel in Jammu & Kashmir by Intercontinental Consultants and Technocrats Private Limited.
Advanced solutions for smart ventilation systems are being provided by multiple key players in the industry, such as Danfoss, Tunnel Tech Solutions Private Limited, ABB India, Acoem India, and Witt India. AC drives provided by Danfoss offer a reliable solution for complex HVAC systems in underground tunnels and subway services, ensuring safe and pollution-free environments for passengers. The key features of these drives include the continuous operation of smoke extraction fans during fires, multi-zone control for independent airflow management and condition-based monitoring for secure uptime. Banana jet fans provided by Tunnel Tech Solutions allow optimal airflow and temperature control and sensors for air quality monitoring.
Technological safety measures
Safety measures in tunnel construction in India are gaining momentum due to an increased impetus on infrastructure development, lessons from past experiences and stricter government regulations. Effective safety measures, when integrated with technological advancements, can minimise project delays, accidents and costs, and enhance public confidence, eventually delivering high quality infrastructure projects.
India has been witnessing rising technology deployments and initiatives to prioritise the safety of workers in tunnel construction, as well as for passengers. Recent tunnel projects in India are being intricately designed following site-specific requirements and established codes, thereby prioritising safety measures essential for emergencies. These measures include escape tunnels, twin tubes with cross passages, separation walls equipped with emergency openings and lay-bys.
Innovations such as artificial intelligence (AI)-based monitoring systems, internet of things (IoT) sensors and wearable technology are being adopted to track workers’ locations and environmental conditions in real time. In line with this, Proxgy, a firm offering IoT-based smart and safety wearables for industrial workers, has launched the Hat+Band and ProHat Band. The Hat+Band converts any standard industrial helmet into an air-conditioned helmet, with around eight hours of battery backup. The ProHat Band transforms standard helmets into smart helmets with features such as audio/videoconferencing, 4G and Bluetooth low-energy connectivity and AI-powered edge processing. This allows for real-time communication and improved situational awareness. Robots equipped with high resolution cameras, infrared sensors and robotic arms were deployed to assess the situation when eight workers were trapped in the Srisailam Left Bank Canal tunnel in Nagarkurnool district, Telangana.
Mature fire protection systems
Fire protection mechanisms and systems in tunnels have been in focus in recent times. These are crucial to ensure the safety of infrastructure, workers and users due to the unique challenges involved in tunnel construction. Fire-resistant coatings and smart sensor technology can further bolster safety measures, enabling proactive maintenance and emergency response. In this direction, Trident Engineering has been contracted to use fire-resistant paint in the Nowshera Tunnel Package 5 project in Jammu & Kashmir. The fire-resistant paint will safeguard the tunnel’s concrete structure, electrical systems and plumbing from potential fire damage. Other examples include the use of advanced fire extinguishers, alarms and smoke detectors, as in the case of twin tube tunnels near Kotla on the under-construction Pathankot-Mandi four-lane project in Himachal Pradesh.
Smart waterproofing solutions
The uptake of enhanced waterproofing methods in tunnel construction is gaining momentum due to the increasing demand for durable and environmentally friendly infrastructure. Effective waterproofing is essential to prevent water ingress, enhance structural integrity and reduce maintenance costs in tunnels, especially for the water supply and irrigation network. Advanced waterproofing techniques with high quality membrane systems, injection grouting and concrete admixtures are being adopted to enhance tunnel longevity. Waterproof membrane systems, such as bituminous or polyvinyl chloride-based sheets, create a barrier against water penetration on tunnel surfaces. Injection grouting seals cracks and joints by injecting materials like cementitious grout or chemical resins. This helps to effectively bind soil and rock particles, thus preventing water ingress into tunnels. Additionally, concrete admixtures are integrated into the concrete mix during construction to boost its inherent waterproofing properties, ensuring a comprehensive approach to tunnel waterproofing.
In sum
India is poised to transform tunnel construction through advanced technology interventions that enhance efficiency, sustainability and safety. With a growing number of underground projects in transportation, hydropower, water resources management, etc., the country is embracing cutting-edge technologies in digital monitoring systems and AI-driven predictive analytics to optimise construction processes. The expansion of metro networks, strategic highway tunnels and water pipeline projects is driving the adoption of automation, robotics and geotechnical innovations to tackle complex geological challenges.
The use of eco-friendly membranes, recycled materials and green materials can minimise the environmental impact of tunnel construction. There is a growing shift from the conventional tunnel construction techniques to the use of tunnel boring machines and the New Austrian Tunnelling Method. These techniques allow for faster excavation, better ground support and more precise tunnel construction. Another new technique, the integrated tunnelling method (known as the Himalayan tunnelling technique) has been used in the newly inaugurated Udhampur-Srinagar-Baramulla Rail Link Project. This technique involves pre-excavation and support measures to stabilise the ground, particularly in difficult terrains and other conditions that are frequently encountered during tunnel construction in the Himalayan region. The other advanced safety features of this project include 67 km of escape tunnels, ballast-less tracks for smooth train operation and advanced cameras at 50 metres intervals that are linked to a central control room for real-time monitoring.
Going forward, the synergy of technology and sustainability will be a key focus for fostering resilient tunnel infrastructure development. This integration is expected to empower data-driven decision-making and deployment of enhanced automation technologies to reduce manual intervention in dangerous stretches of tunnel construction. This will help ensure long-term durability and cost-effectiveness in future projects.
