Microtunnelling

Microtunnelling is a trenchless underground construction method used for installing pipelines or conduits. It is a remote-controlled process, typically employing a microtunnelling machine (MTM) to excavate the soil and simultaneously install pipes behind the machine. This method is suitable for a range of ground conditions and is often chosen for its minimal surface disruption, making it ideal for urban areas, sensitive environments, and crossing obstacles like roads and railways.

The process begins with the excavation of a launch shaft and a reception shaft. The microtunnelling machine is then launched from the entry shaft. The MTM consists of a cutting head that breaks up the soil, a slurry or spoil removal system that transports the excavated material back to the surface, and a jacking system that pushes the pipes into the ground. As the machine advances, pipes are connected and jacked behind it, forming a continuous conduit. Guidance systems, often laser-based, ensure the MTM follows the planned alignment and gradient with high precision.

Advantages of microtunnelling include reduced excavation depth compared to traditional trenching, minimal impact on existing infrastructure and surface activities, and the ability to install pipes in areas with high water tables. It also offers a high degree of accuracy in alignment and gradient control. The method is particularly effective for smaller diameter pipes and for installations where surface disruption must be kept to an absolute minimum. Applications include the installation of utilities such as water, sewage, gas, and electrical conduits.