What is microtunnelling and why is it used?
Microtunnelling is a technique used to install a tunnel structure beneath ground, which a pipeline can be inserted through. It is classed as a non-disruptive technique as it does not impact the surface, meaning that roads, railways and watercourses can stay open while habitats and ecosystems remain undisturbed during construction.
The process involves utilising a microtunnel boring machine (MTBM), which is remotely operated from the surface by a skilled operative. The MTBM is guided by a laser and driven forwards by hydraulic jacks. Each time the hydraulic jacks extend, this pushes forwards the MTBM, as well as a concrete jacking pipe, which is situated immediately behind the MTBM. Each time the MTBM is driven forwards, new concrete jacking pipes are lowered into place until the tunnel is completed. These concrete jacking pipes will form the completed tunnel structure.
More information about microtunnelling is available here.
How long will it take and when will the microtunnelling take place?
The duration of the microtunnelling works for the Pipeline will vary depending on the location, size and geotechnical complexity of each crossing.
Image of a jacking ring being driven behind a TBM that was used by UI, in collaboration with Joseph Gallagher Limited