What’s New in Tunnel Boring Machine Technology?

By Emily Newton

Necessity is the mother of invention. Consequently, tunnel boring machinery has undergone rapid innovation over the past few years. Needs for affordability, reliability, precision and more are rising, and technology holds the answers.

Heavy industries as a whole are embracing digital transformation at an unprecedented rate and tunnel boring machines (TBMs) are no different. While the basics of these machines have remained unchanged for generations, the newest iterations are a far cry from the mechanical giants of yesteryear. Here’s a look at some of the most significant innovations.

IoT Connectivity

The Internet of Things (IoT) is a game-changing technology for heavy industries. These interconnected sensors provide access to real-time data for more precise and efficient operations. It’s no wonder, then, that the industrial world has implemented more than 17 billion of these devices.

TBMs benefit from IoT connectivity in several ways. The most straightforward use case is creating monitoring operational metrics like cutting rate, machine temperature, torque and speed. IoT sensors can show this data in real time so operators can make more informed decisions or respond to emergencies faster.

Predictive maintenance is another key use case for the IoT in TBMs. This involves using IoT data to predict equipment failures so technicians can repair issues while they’re still small. Maintenance times and costs both fall as a result.

Automated TBMs

Automation is another technology making waves in tunnel boring operations. The wealth of data IoT sensors provide makes it easier for automated programs to control TBMs with minimal to no human input.

Automated TBMs are less likely to make costly errors, as machines cannot get distracted and work solely off of hard data. They also improve workplace safety. Just as hydraulic shoring is one of the most popular trenching methods because it minimizes workers’ time in the trench, automated TBMs enhance safety by reducing time in the tunnel.

Driverless technology may not be reliable enough for cars yet, but TBM routes are far more direct and don’t risk running into other vehicles. Consequently, today’s machine learning algorithms are more than safe enough to direct this equipment. On top of the safety and productivity benefits, this automation offsets labor shortages.

Plasma and Gas Tunneling

Mechanical excavation equipment has become far more efficient and cost-effective, but physical contact will always introduce challenges. Consequently, some TBM manufacturers are starting to implement gas or plasma-based cutters instead.

Using these high-temperature cutters prevents mechanical contact between the TBM and the ground to minimize vibrations, resistance and torque. TBMs can last far longer and experience fewer maintenance issues as a result.

Gas and plasma cutters work faster than conventional methods, too. One plasma system claims to be 100 times faster than mechanical cutters, leading to more cost-efficient operations. Without as many repairs or having to be on-site for as long, tunneling companies can dramatically reduce their expenses per project.

Adaptive Tunneling

Ground conditions are rarely perfectly consistent, and some tunnels must shrink or expand in certain areas to suit their end uses. Historically, this has meant tunneling teams must pause operations and switch out equipment, but newer TBMs can adapt without lengthy changeovers.

This adaptivity can come in several forms. Some new TBMs are modular, letting teams switch their drilling equipment instead of changing machines entirely. That can include changing the cutting mechanism for harder or softer ground, or switching to a smaller diameter to bore smaller tunnels.

Adaptability can also stem from IoT systems. Real-time sensors can detect when ground conditions change and automatically adjust drill speeds or torque in response. These on-the-fly adjustments ensure automated TBMs can accomplish more projects without intervention.

Continuous Excavation

Similarly, newer TBMs can accommodate continuous excavation. Traditional equipment requires frequent pausing to remove debris or build tunnel rings, leading to long project timelines. Modern models can handle these tasks as they drill, significantly improving efficiency.

Waste removal systems are among the most common of these continuous excavation approaches. Funnels, suction systems, or compressed air can move or blow excavated material out of the way as drills advance. Teams still need to remove this debris after the drill passes, but they can do so as the TBM plows ahead instead of stopping operations.

Other TBMs use real-time analytics technologies to determine how much pressure to direct to different cylinders across the length of the machine. That way, they can dig efficiently while ensuring tunnel ring installation can happen safely behind the drill.

Sustainable TBM Design

Tunnel boring technology is also moving toward sustainability. Conventional tunneling methods are energy-intensive and environmentally destructive, but newer options can perform the same work with less environmental disruption.

Electrification is the most significant shift in this movement. Electric TBMs are becoming increasingly common and substantially reduce greenhouse gas emissions from tunneling operations. More efficient drill heads or plasma tunneling have similar effects, as they require less power to operate.

Of course, electrification itself isn’t a perfect solution. Roughly 40% of CO₂ emissions stem from fossil-fuel-powered energy plants, but this is changing. Renewables like solar and wind are growing, offering truly emissions-free tunneling power. Some TBMs even connect directly to above-ground solar panels for zero-emissions operations.

Microtunneling

As the name implies, this involves using compact TBMs to dig smaller-diameter tunnels. These often remote-controlled or automated machines enable higher precision and less disturbance to the surrounding environment or nearby infrastructure.

The U.S. is home to over 2.6 million miles of oil and gas pipelines alone, not counting other utility tunnels, sewers or underground roadways. Consequently, it’s getting more crowded underground. Micotunneling lets teams build underground infrastructure without running into these existing tunnels or weakening the soil too much, endangering above-ground structures.

Microtunneling is also more energy and cost-efficient. Smaller TBMs don’t require as much power, so they can finish the job with fewer emissions and in shorter timelines.

New Technology Unlocks New Tunneling Possibilities

Tunneling technology is changing rapidly because it must. The industry faces higher demands than ever before, but innovation provides a way around these obstacles.

Implementing these technologies does more than simply help businesses overcome lingering challenges. It opens the door to new heights of profitability, sustainability and efficiency, ensuring ongoing success.

Emily Newton is a construction and industrial journalist. She enjoys exploring the impact technology has in the construction and utilities sectors. When Emily isn’t writing, she enjoys building Lego sets with her husband.