Microtunnelling used to be classed as “non man entry” bores using laser guidance for high accuracy drilling and all directional steering. The technology now encompasses bores from 150mm to 3.5m in diameter in most types of ground conditions. Microtunnelling is used for high accuracy, fine grade gravity sewers, stormwater systems and outfall pipelines. The cuttings are removed in a slurry and cleaned with a closed-loop recycling system or through the use of continuous flight augers. Alternatively, vacuum extraction micro-tunnellers use vacuum systems to remove the cuttings.
JTP Consulting staff have been involved in many complex microtunnelling projects encompassing deep shaft construction, drilling and pipe installation. Many of the crossings have been below the water table river crossings. We provide site investigations, route planning, pipe design, methodology (independent of contracting companies pushing their own technologies), specifications and contract documentation.
A variety of pipe materials may be used in the construction of the pipeline. The product pipe is usually installed as the cutter progresses, although free bores in shales and rocks can be achieved in competent ground with the product pipe being installed on completion of the bore.