Mechanised Tunneling Techniques Transforming Tunneling Industry

Mechanised techniques are gradually replacing traditional or non-mechanised methods of tunnel construction in the country. Advanced, technology-driven, efficient and cost-effective methods of tunnelling are being deployed in almost all infrastructure sectors. While the mechanised techniques usually involve higher equipment and transportation costs as compared to the traditional tunnelling techniques, they offer speedy project completion, thereby enabling faster inflow of revenues.

Tunnels play a crucial role in setting up hydropower projects, developing urban mass rapid transit systems, improving road and rail connectivity and facilitating water and irrigation projects. There has been a rise in tunnelling activity in the country, as a large number of infrastructure projects are being implemented across sectors such as railways, roads and highways, water supply and sewerage, and urban mass transit. Over the past few years, the tunnel segment has received greater attention due to increased congestion in urban areas, which has left little scope for on-ground construction. As a result, newly evolving tunnelling techniques offer greater flexibility to contractors.

The New Austrian Tunneling Method (NATM) is an innovative approach to tunnel construction that has been gaining popularity in recent years. NATM is a flexible and adaptable method that allows for the construction of tunnels in a variety of geological conditions, including soft ground, hard rock, and mixed conditions. This method also allows for the construction of tunnels with complex shapes and cross-sections. Additionally, the method is relatively fast and cost-effective, as it eliminates the need for extensive pre-support measures, while also improving safety and minimizing environmental impact. NATM is not just a construction method for performing tunneling operations, but also an approach towards a streamlined sequence of the necessary construction activities with security, safety, and economy being the pivotal elements. NATM is fast emerging as an alternative to traditional tunneling methods in congested urban areas especially in metro rail sectors. It is also a preferred method for tunnels in mountains with uncertain geological and hydrogeological conditions. Besides, it is appropriate for construction of approach roads of adequate geometry for caverns and mines.

The development of tunnel boring machine (TBM) has revolutionized the tunnelling industry by making tunnelling a safer, more economical solution for creating underground space and opening the possibility of creating tunnels where it was not feasible before. This highly mechanized tunnelling method, TBM is well known throughout the world for achieving very high tunnelling rates and adoption of such method in projects can speed up considerably the completion of the project within the stipulated time schedule. Tunnel boring machines are the best choice for use in densely populated regions since they minimize disruption in the excavation area. Additionally, they provide a smooth tunnel wall, which lowers the price of the finished lining. When compared to traditional excavation techniques, TBMs considerably shorten the overall excavation time of longer tunnels. The use of TBMs is the most prominent in the irrigation and water supply, sewerage and metro rail sectors for tunnel construction in congested urban areas. These machines are being custom-made to deal with site-specific requirements of projects.