Microtunnel Boring Machines (MTBMs)
Microtunnel Boring Machines (MTBMs) install gravity flow pipelines that require precise line and grade in poor soil. Microtunneling is a remote-controlled, continuously supported pipe jacking method. Standard center drive and face access, peripheral drive MTBMs are sized in the 30-114-in. OD range. Microtunneling operations are managed by an operator in an above ground control container alongside of the shaft. Soil excavation takes place by way of infusing the soil with slurry at the face of the bore and cuttings are forced into slurry inlet holes in the MTBM’s crushing cone for circulation to and from a separation plant through a closed system. A complete slurry microtunneling system commonly comprises a pipe specific MTBM, control container, guidance system programs, remote hydraulic power pack, keyhole jacking frame, a series of pumps, laser, water cooling tank, slurry and additional lines, and a slurry separation plant. The launch shaft is outfitted with a pit seal to prevent shaft flooding and a project specific thrust block to distribute jacking force.