When failure strikes, precision recovery makes the difference
A Critical Situation for Any TBM Project
Damage to the main drive of a Tunnel Boring Machine (TBM) is one of the most serious incidents a tunnel engineer can encounter. Depending on the extent of the failure, the consequences can impact the entire project timeline, budget, and safety conditions.
Case Study: From Breakdown to Controlled Recovery
In one of our most demanding interventions, we faced the breakdown of a pinion inside the main drive. The failure caused fragmentation, and the debris damaged several teeth of the main gear. This incident had the potential to halt the project indefinitely.
Instead of disassembling and removing the TBM underground — an operation involving extreme cost and time — we opted for a controlled, step-by-step solution.
Our Approach
The damaged main gear was repaired in place using precision welding and grinding techniques, restoring the correct geometry and resistance of the affected teeth.
The damaged main gear was repaired in place using precision welding and grinding techniques, restoring the correct geometry and resistance of the affected teeth.
A robust set of real-time monitoring tools and protocols was implemented:
Continue advancing the TBM until it reached a safe location — such as a shaft or station — where a complete replacement of the bearing and gear could be executed properly.
Results
Hyperbaric operations require a well-defined protocol before, during, and after the intervention. Key steps include:
The TBM successfully advanced without additional damage
The main gear reached the replacement zone in optimal conditions
Downtime and financial loss were significantly minimized
