Direct Pipe is a single pass process that uses a steerable tunnel boring machine-cutting head. The technology tunnels and pushes the pipe into place at the same time, filling the void as it progresses. This technology greatly reduces the likelihood of hydraulic fracture and inadvertent returns and is ideal for crossing under levees and environmentally sensitive areas.
Direct Pipe benefits:
. More effective for difficult subsurface formations than HDD installation.
. Direct Pipe can handle gravel and cobbles up to approximately 1/3 the size of the Direct Pipe machine (i.e. 10-in. cobble for a 30-in. Outside Diameter Direct Pipe Machine).
. Ideal for crossing under levees and sensitive environmental areas.
. Significantly lower annular pressure acting on the surrounding subsurface formation.
. Ideal for shore approach and/or outfall pipelines.
. There is no need for marine support until the Direct Pipe machine breaches the seafloor.
. Significantly less volume of bentonite released to water.
. Reduced potential for inadvertent returns.
. Drilling fluids transported to head and back via umbilicals.
. Improved site safety.
. One step process of pushing tunneling equipment and pipe, with no rotating equipment above ground.
. Reduced workspace requirements at crossing.
. The equipment and pipe stringing are on the entrance side of the crossing.
. A small pit, slightly larger than the normal pipe ditch is all that is required on exit.
. Less pipe required for crossing.
. Shorter and shallower crossing plan and profile configuration.