Freebore Microtunnelling Method | Pezzimenti Tunnelbore

WHAT IS FREEBORING?

Freeboring is the microtunneling method used when the ground conditions are self-supporting – while microtunneling there is no need for an outer jacking pipe to provide ground support. Compared with Pipejacking, the Freebore Microtunnelling method is much faster and it’s much easier to access the microtunnelling head in case of obstructions or maintenance is required.

Freebore Microtunneling Pezzimenti

Completed Freebore is Self Supporting Sandstone

Freebore Microtunneling Pezzimenti

The rods during microtunneling using the Freebore Method

Freebore microtunneling Pipe Sliplined into a Freebore

Inside the freebore which was completed in very hard rock.

Freeboring Microtunneling Methods

There are 3 primary outcomes for all microtunneling and pipe installations. These are the

Free Pipe – Carrier Pipe is grouted into a microtunneling where the ground is self supporting.
Close Fit Pipe – Carrier Pipe is also the Casing Pipe. Use for projects where the gap between Pipe OD and Microtunnel ID is less than 25mm, and;
Pipe-in-a-Pipe – A carrier Pipe sits within an Outer Casing Pipe.

Freebore Microtunneling method can achieve them all as outlined below.

Microtunneling-using-Freebore-Method-to-achieve-Free-Pipe-Outcome

Free Pipe Method.

Step 1. The ground has been determined to be self-supporting and is microtunnelled without the need for ground support. Step 2. The Carrier Pipe is sliplined into the microtunnel and the annulus space is grouted.

Close-Fit Pipe – Freebore Method

Step 1. The ground has been determined to be self supporting and is microtunnelled without the need for ground support. Step 2. The Casing Pipe, which is also the carrier pipe, is sliplined into the microtunnel. Ideal for designs where the between the Casing Pipe OD and the Microtunnel is < 25mm.

Microtunneling using freebore method to achieve Pipe in a Pipe outcome

Pipe in a Pipe – Freebore Method

Step 1. The ground has been determined to be self supporting and is microtunnelled without the need for ground support. Step 2. The Casing Pipe is sliplined into the microtunnel. Step 3. The carrier Pipe is sliplined into the casing pipe.