Minimizing impact, maximizing tunnel continuity
What Are False Tunnels?
At the launch of any Tunnel Boring Machine (TBM), it’s common to find a false tunnel section, typically around 7 rings long, located between the push frame and the diaphragm wall. These temporary structures are also frequently encountered at intermediate shafts and when TBMs must cross short ventilation shafts.
In such cases, advancing the TBM by installing full rings is often more efficient than setting up a dedicated push frame.
Why and When to Disassemble?
False tunnels are designed to be temporary. Depending on the project schedule and design constraints, disassembly becomes necessary in several scenarios:
Our Disassembly Approach: Safe and Non-Invasive
While segment demolition may seem like the quickest solution, it causes several weeks of disruption to the tunneling operation. Instead, we use a controlled disassembly method, removing complete segments without destructive techniques.
This process has multiple advantages:
Minimal impact on ongoing TBM activity
Can be performed in phases, coordinated with scheduled TBM maintenance stops
Reduces costs and avoids unnecessary delays
Each case is unique. That’s why we conduct a detailed project analysis to determine the best solution, based on available equipment, time constraints, and structural considerations.
Our disassembly methods have been successfully applied on projects where TBM advancement continued uninterrupted, proving the effectiveness of this non-invasive solution.
