Microtunneling is a process that uses a remotely controlled Microtunnel Boring Machine (MTBM) combined with the pipe jacking technique to directly install product pipelines underground in a single pass. This process avoids the need to have long stretches of open trench for pipe laying, which causes extreme disruption to the community. In the U.S., microtunneling has been used to install pipe from 12 inches to 12 feet in diameter. Therefore, the definition for microtunneling in the U.S. does not necessarily include size. Microtunneling has evolved in the US to describe a tunneling process where the workforce does not routinely work in the tunnel. Microtunneling is currently the most accurate pipeline installation method. Line and grade tolerances of one inch are the microtunneling industry standard. This can be extremely important when trying to install a new pipeline in an area where a maze of underground utility lines already exists. Although originally designed for gravity sewer construction, microtunneling installations include underground crossings of highways, railroads, runways, rivers, and environmentally sensitive areas for a variety of utilities. This process has also been used to install plant intakes and outfalls. Microtunneling is also used in the pipe arch technique of supporting large underground openings with an arch or roof made up of small tunnels.

Microtunneling uses all of the following features during construction:

Remote controlled - The microtunneling boring machine (MTBM) is operated from a control panel, normally located on the surface. The system simultaneously installs pipe as spoil is excavated and removed. Personnel entry is not required for routine operation.

Guided - The guidance system usually references a laser beam projected on to a target in the MTBM and is capable of installing gravity sewers or other types of pipelines to the required tolerance for line and grade.

Pipe jacking - The process of constructing a pipeline by consecutively pushing pipes and MTBM through the ground using a jacking system for thrust.

Continuously supported - Continuous pressure is provided to the face of the excavation to balance ground water and earth pressures

Walter C. Smith Co.’s engineers can tell you if this method of installation would be best for your project. Contact us at (559) 299-9727 or e-mail us at This e-mail address is being protected from spambots. You need JavaScript enabled to view it .