Definition - What does Microtunnelling mean?
Microtunneling is a method of trenchless construction in which holes are bored and pipes are laid through remote guidance, pipe jacking and continuous support. The microtunneling boring machine (MTBM) is operated from a control panel, normally located on the surface. The system simultaneously installs pipe as the ground is excavated and removed. Personnel entry is not required for routine operation.
Trenchlesspedia explains Microtunnelling
At its foundation, microtunneling is essentially remote pipe jacking. However, due to its cost, microtunneling is usually reserved for pipes which need a high degree of precision over a long distance. The cutting head during the boring stage is accomplished via water jetting, or an asymmetrical or slanted head; it is laser directed. Pipes of diameters up 120 inches in diameter can be installed with this process. Only pipes with a circular cross section can be used because of the boring process.