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Tunnel Construction Services

Microtunneling is a process that uses a remotely controlled Microtunnel Boring Machine (MTBM) combined with the pipe jacking technique to directly install product pipelines or casing underground in a single pass.

Huxted Microtunneling Services

Long Drives

With years of Microtunneling history, Contractors have now developed means and methods that allow long drives (tunnels) to be constructed. Drive lengths in excess of 3000 feet have been completed, including those with curves. Most of these are in pipes larger than 36 inches in diameter. These longer drives allow for crossing larger bodies of water, environmental sensitive areas or simply to minimize road or urban disruption.

Curved Drives

Curves, whether vertical, horizontal or compound have been completed today. Using sophisticated guidance systems, such as gyros, prisms, and other survey equipment, the location of the microtunneling machine is always known, as such, the machine can be surveyed and guided on a designed curve. Curves allow for installation of pipe lines around, under or over sensitive areas and obstacles (such as bridge pilings, manholes, other utilities, building foundations, etc.).

Intakes & Outfalls With Underwater Recovery

Since the microtunneling machine provides hydrostatic counterbalance while under operation or not, the microtunneling method is typically used in the construction of many intakes and outfalls. Most intakes and outfalls are located underwater, as such, conventional “open face” machines would flood or expensive cofferdams would have be built in environmentally sensitive areas to retrieve conventional machines.

Marine / River Crossings

Since the microtunneling machine provides hydrostatic counterbalance while under operation or not, the microtunneling method is typically used in the construction of pipelines under rivers, creeks, streams, bays, etc. as the soil underneath these marine environments are usually wet and fully saturate due to the hydrostatic contact of the marine body that is being crossed.

Cost Effective / Environmental Crossings

Most environmentally sensitive areas are typically wet lands. Since the microtunneling machine provides hydrostatic counterbalance while under operation or not, the microtunneling method is typically used in the construction of pipelines under environmentally sensitive areas. As the soil underneath these marine environments are usually wet and fully saturate due to the hydrostatic contact of the marine body that is being crossed. In addition, the microutnneling machine is an earth pressure balance machine, thus protecting the hydrostatic conditions and preventing settlement and/or heave of the surface.

Minimal Disruption

The microtunnel operation can install thousands of feet of pipe working out of one, relatively small location, as compared to the open cut operation, that requires large areas of disturbance, including complete lane closures, traffic detours, noise and dust issues. Therefore the microtunneling method is more friendly to the community, the public and the environment.

Railroad / Highway Crossings

Since the microtunneling machine provides hydrostatic counterbalance while under operation or not and earth pressure balance control, the microtunneling method can be used in the construction of pipelines under Railroads, Highways, Interstates, etc. without the interruption of traffic or railways.

Precision

Microtunneling was originally designed for the installation of sanitary sewers, as such, the pipeline can be installed to a tight tolerance. This is helpful with microtunneling projects that require very sensitive grades or have underground obstacles to avoid.

Our Tunnel Construction Services at Work:

Stiles Vortex Outfall

For this microtunneling project, Huxted installed 250 ft of 84 inch RCP with an underwater machine recovery in the Mississippi river for a new waste water outfall. Ground conditions included sand and silt. The machine was launched from a 24 ft diameter shaft 60 feet deep.

Location: Memphis, TN
Date: Early Spring 2017
Owner: City of Memphis

U.S. 41 MICROTUNNEL/WEIRS PROJECT

This microtunneling project included the installation of 320 feet of 60 inch RCP in 2 drives and 884 feet of 84 inch RCP in 5 drives for new drainage lines under U.S. Highway 41. All tunnels were designed, constructed and completed with less than one diameter of cover between the top of the Highway and the top of the pipe. Soil consisted of fine grained sand with some silt.

Due to the alignment of the tunnel compared to the Highway, the machine was launched and recovered at a 53 degree angle to the face of the shaft wall. In addition, the MTBM recovery location was located immediately under high voltage transmission lines.

Location: Port Charlotte, Florida
Date: Spring/Summer of 2014
Owner: Charlotte County, Florida

84” UTILITY CONDUIT INSTALLATION

This microtunneling project involved a 580 foot Installation of 101.5 inch OD Reinforced Concrete Pipe in a 700 foot radius curve at a depth of over 50 feet by Microtunneling. Soil consisted of sandy silt with gravel. A VMT Guidance and Jack Control System were used to provide guidance and control of the curved alignment. Surveyed results were within ½ inch of design grade and line. Due to the location of this microtunneling project, security constraints required the tunnel to be constructed inside two separate buildings. One building housed the separation plant and the other housed the launching shaft and pipe storage.

Location: Washington, DC
Date: Winter of 2014/2015
Owner: U.S. D.O.D.

PARADISE POWER PLANT RAW WATER INTAKE

This microtunneling project included the installation of 345 feet of 36 inch steel pipe with an underwater recovery for a raw water intake at the new Paradise Combined Power Plant. Ground conditions consisted of Clay, silty clay with some sand. The MTBM was launched out of a 20 foot diameter caisson and recovered in the river with a barge mounted crane and divers.

Location: Drakesboro, KY
Date: Spring 2016
Owner: Tennessee Valley Authority

Safety is Our #1 Priority

We are committed to achieving an accident free workplace during evry phase of our microtunneling construction. Proactive involvement, personal responsibility, personal accountability, and continuous individual improvement are expected of all employees, subcontractors, vendors and clients. Safety is of utmost importance in the planning of all microtunneling services, and every one of our employees embrace his/her role in successfully implementing our Safety Program.

Learn More About Our Safety Program