We anticipate increased adoption of tunnelling systems across all sectors in the coming years

How is the development of road and railway tunnel projects progressing in the country?

India's infrastructure development is accelerating, driven by strong government focus and substantial investment in road and railway tunnel projects, particularly in challenging terrains like the Himalayas and urban metro areas. Utilizing advanced techniques such as Tunnel Boring Machines (TBMs) and the New Austrian Tunneling Method (NATM), numerous projects are underway, including significant railway tunneling in the Jammu Kashmir link and metro expansions in major cities. Road tunnel projects within cities are also being developed to improve traffic flow.

How are underground and mountain tunnel projects helping in creating better connectivity infrastructure?

Mountainous regions are prone to extreme weather conditions such as heavy snowfall, landslides, and avalanches, which can affect transportation. Tunnels offer reliable, year-round access, ensuring consistent connectivity. They create direct routes through mountains, significantly reducing travel distances and times compared to winding mountain roads. In strategically important areas, tunnels provide secure and efficient transportation routes for both military and civilian purposes.

Underground tunnels, especially for metro rail systems, offer alternative transportation routes, alleviating surface traffic congestion and enhancing urban mobility. In densely populated urban areas, underground tunnels make effective use of limited space, allowing for the development of transportation infrastructure without disrupting surface activities. Tunnelling also reduces pollution which is a big menace these days. 

How is technology evolving in tunnelling? How are technologies such as TBMs making tunnelling productive and efficient?

Modern TBMs are equipped with advanced cutting heads designed to handle various geological conditions. They also include systems for segment lining installation, making the process more efficient. Automation is increasingly being used in tunneling, with robotic systems managing tasks like segment placement and material transport. This reduces the need for manual labor, improving safety and efficiency. Sensors and monitoring systems provide real-time data on ground conditions, machine performance, and structural integrity. Data analytics and machine learning algorithms optimize TBM operations, predict maintenance requirements, and enhance safety.

TBMs can excavate continuously, unlike traditional methods that involve drilling and blasting. They offer precise control over the excavation process, minimizing over-excavation and reducing the need for rework. Additionally, they reduce workers' exposure to hazardous conditions, thereby improving overall safety.

What are the major challenges encountered in tunnelling? How are you minimising the challenges?

Working at congested area: Working in congested areas presents several challenges, including material and equipment movement, the health of nearby existing buildings, limited working space, and the risk of settlement or damage to existing structures.

Some of the mitigating measures we are taking are plan traffic diversion of routes with local police, monitoring nearby buildings for settlement or cracks using sensors, strengthening nearby structures to minimize damage, and designing decking to create working space.

Diversion of underground utilities and transit lines: Challenges include identifying utilities, encountering unknown utilities, seeking approval time for diversion, and managing closure or repositioning at project completion.

To mitigate risks, we collect data and seek clarification during the tender stage, have a dedicated team to identify utilities and plan diversions with proper documentation, and proactively coordinate with clients and government bodies for approval.

Risk of water seepage: The concerns include ground instability increasing the risk of collapses or cave-ins, excessive water ingress causing flooding within tunnels or shafts, construction delays due to dewatering, grouting, or other waterproofing systems, and cost overruns as addressing water seepage issues typically requires additional resources, materials, and labor.

As part of mitigation measures, 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.

Which are the key tunnel projects done by the company? What are the technologies used at these projects?

Tata Projects began tunneling work in 2016 with the Lucknow Metro. We have since completed Mumbai Metro Line 3 and Pune Underground Metro. Currently, we are working on the Chennai Metro Rail and Ramban Banihal Road Tunnel.

Our tunneling techniques include:

·   Bored Tunnel using a TBM: Ideal for consistent geology and long tunnels.

· New Austrian Tunneling Method (NATM): Useful in areas with rapidly changing geology where rock mass forecasting is challenging.

· Cut & Cover: Traditional method used mainly for underground stations and ramps, involving excavation, construction, and backfilling to restore the surface.

Which are your key tunnelling projects in the pipeline? How do you look at the opportunities?

There are several tunnel projects in progress across Metro Rails, Rapid Rail Transit Systems, Indian Railways, Roads, and Pump Storage Projects (PSPs) & Water sectors. Clients such as Maha Metro, MPMRCL, UPMRCL, and DMRC in Metros; NHAI, MMRDA, and BBMP in Roads; NCRTC, Indian Railways, and RVNL in Rail/Rapid Rail Transit, along with various large municipal corporations and private developers in the water sector and pump storage projects, are initiating tunnel systems for bulk water transmission.

This presents a significant opportunity for tunnel systems in the country across multiple sectors, which is a development we find very promising. Metro projects are now extending to Tier-2 cities, including Indore Metro and Patna Metro. Although tunnel systems are challenging and costly, they provide an efficient solution amidst constraints such as land availability, right-of-way issues, and statutory clearances. Tunnel systems will undoubtedly facilitate the timely creation of infrastructure necessary to support economic growth.

What is your outlook on the growth of tunnelling in the coming years?

Tunnelling systems have grown slowly, with cheaper alternatives explored first. However, as India aims to double its economy to $7 trillion by 2030, timely infrastructure delivery becomes crucial. Developers, both government and private, are now factoring in delayed market entry costs and revenue losses, making tunnelling systems more viable in life cycle costs. We anticipate increased adoption of tunnelling systems across all sectors in the coming years.