Microtunneling

Microtunneling

Microtunneling is the method of choice when the installation has to be deep, accurate and below the water table, and when settlement at the surface is simply not acceptable. A remotely operated microtunnel boring machine is jacked forward from a launch shaft while pipe is installed directly behind it, with the excavation face under continuous pressure support for the entire drive.

That face support is the defining characteristic. Because ground is never left unsupported, the method works in running sand, soft silt and full hydrostatic head — conditions that would make augering or open cut impossible — while holding line and grade to the tolerances a gravity sewer demands over hundreds of metres.

It is the most equipment- and engineering-intensive method we operate, and we recommend it where those conditions genuinely apply: deep trunk sewers, crossings beneath rivers and rail corridors, and work under city streets where surface settlement would damage adjacent structures.