What Does Utility Tunneling Mean?
Utility tunneling is a trenchless construction method that requires workers to enter the borehole. It is similar to pipe jacking but uses temporary support structures like concrete liner plates, wood lagging systems or steel ribs to provide a shield for workers and to secure the tunnel. The utility tunneling method involves the installation of a liner that acts as a continuous support structure at the front cutting face where the soil is removed by excavation.
Trenchlesspedia Explains Utility Tunneling
The utility tunneling method involves a few steps:
- Soil excavation
- Spoil removal
- Liner installation
The excavation process depends on the type of soil removed and the conditions of the site. The excavation is done by hand mining, partial-face mechanical tunneling or using a tunnel boring machine (TBM). While excavating the tunnel, workers must ensure that the grade, or angle, on the excavation and direction are on track.
Spoil removal can be done using vacuum extraction, wheelbarrows or carts, or conveyors. Finally, the liner is installed, which works to support the tunnel and protect the utilities that run through it. Liner construction can be either steel or reinforced concrete.