Retractable Head – Microtunnelling with No Exit Shaft

Advantages to Blind Boring

A major advantage of the retractable head microtunnelling system is that no exit shaft is required when the work is commenced. This allows microtunnelling to be planned for completion outside of project pressures and time constraints, and may significantly reduce overall project costs.

An exit shaft does not require maintenance, securing or traffic control until the works require it, with pipes being installed at the required distance, the retractable head retreived from the entry shaft.

Drilling into Manholes

The same method allows drilling into existing manhole bases. A microtunnel is completed to the exterior of the manhole base, retracted and replaced with the coring head, then pushed back to the manhole to core through*. The core is retrieved to the entry shaft and the carrier pipe sliplined to the base of the manhole.

* Depending on ground condition it may be possible to continue into the manhole base without changing to the corer head. 

No Exit Shaft Retractable Head Microtunnelling

01. Launch Retractable Head

The retractable microtunnelling head is launched from the entry shaft with no exit shaft required.

No Exit Shaft Retractable Head Microtunnelling

02. Microtunnelling

The microtunnel is completed to the required length for future works.

No Exit Shaft Retractable Head Microtunnelling

03. Microtunnelling Head Retracted

The head is retracted and removed via the entry shaft while outer casing / carrier pipes remain at rest.

04. Slipline the Carrier Pipe (If Required)

If required a carrier pipe can be sliplined into the outer casing to be grouted when future works come through.

No Exit Shaft Retractable Head

05. Pipes Installed

Pipes are now installed and ready be discovered as required by future works – with no maintenance, security or traffic control required where an exit shaft would usually be.

Book a Presentation

For futher information on Retractable Microtunelling Head Capabilities and Methodologies book a presentation for your design team with Pezzimenti today. Call Scott Wells on: +61 (2) 4735 6676 or email