Boring Company Path to Continuous Tunneling

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Boring Company Prurfock 3 and the new Prufrock 4 tunneling machines can only tunnel about 11 hours per day. There are limitations are maintenance and how they have to stop tunneling to put in the concrete segments.

The Boring Company likely has a program to rapidly develop and test new machines to reach the goal of Continuous Tunneling. This likely will require new gripper tunneling machines.

This would finally enable about a doubling of daily tunneling from about 40-46 meters per day to 85 meters per day in 2025 and then 120 meters per day in 2026. This is from analysis by the youtube channel Boring Revolution.

Gripper Tunneling Machines are designed for tunneling through hard rock, offering several advantages for faster and more continuous tunneling:

Mechanism: A Gripper TBM uses a rotating cutterhead equipped with disc cutters that apply significant pressure (up to 32 tonnes per disc) against the tunnel face. The machine’s design includes gripper shoes or plates which brace against the tunnel walls, allowing the thrust cylinders to push the cutterhead forward. This setup eliminates the need for continuous segment lining, which is typically required in softer ground conditions, thereby speeding up the tunneling process.

Advance Rates: In suitable geological conditions, where the rock is strong enough to support itself without immediate lining, Gripper TBMs can achieve high advance rates. This is due to their ability to move forward without the need to stop for lining installation, which is a significant bottleneck in traditional tunneling methods.

Continuous Tunneling: The concept of continuous tunneling with Gripper TBMs involves minimizing downtime. Here’s how it’s achieved:

Immediate Rock Support: Behind the cutterhead, systems for immediate rock support like rock anchors, steel mats, and arches are used in what’s known as the L1 working area. This setup allows for continuous excavation without the need for extensive lining, which would slow down the process.

Material Handling: The excavated material (muck) is efficiently handled through integrated muck chutes and conveyor systems, reducing the time spent on material removal and allowing for a more streamlined operation.

Adaptability: Gripper TBMs can adapt to varying geological conditions through the use of radial boreholes for rock anchors, ensuring stability and safety, which indirectly contributes to faster tunneling by reducing the need for extensive safety measures that might slow down the process.

Automation and Data: The integration of automation, like the autonomous TBM (A-TBM) systems, could theoretically be applied to Gripper TBMs to optimize their operation, reducing human error and increasing efficiency.

Continuous Tunneling in Soft Ground: While this technology was mentioned for soft ground, the principle of continuous operation without stopping for lining could inspire similar innovations for hard rock tunneling with Gripper TBMs.

2 thoughts on “Boring Company Path to Continuous Tunneling”

  1. Why mess around with grippers when you could just add steel ballast? A 5000 tonnes of steel only costs a couple of million, and gravity + friction works regardless of earth conditions.

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