Microtunnelling is an efficient and environmentally friendly alternative to open-trench construction of many structures and outdoor spaces. This trenchless technique offers precise line and level installations in various ground conditions (including rock) and commercial grade equipment to make it happen.
Most of the functions of the microtunnelling operation are computer controlled or assisted. It is accurate to industry standard tolerances and thus is suitable for gravity sewer installations. The machines can be operated from either shafts of cofferdams.
Microtunnelling is particularly suited to the urban environment where the disruption of business, traffic and other utilities is not acceptable for commercial, political and safety reasons.
The majority of microtunnelling work is carried out using slurry TBM’s (Tunnel Boring Machines). These offer the ability to work below the water table, using the slurry as a transport medium for the excavation arising and to balance the ground water pressure. Excavated material is separated from the liquid by a specialized plant situated at ground level. The liquid is then recycled, being sent back to the TBM and forming a closed loop system. This method of excavation also enables construction of pipelines within challenging ground conditions without any type of pre-treatment or ground water control. This type of TBM can also be configured to work in rock.
Another of the advantages provided by microtunnelling is the minimal ground movement caused during installation