Overview

What is Trenchless Construction?

In Northern America, we are fortunate to live in a modern era where heat, plumbing, electricity and internet are services we take for granted. We simply program a thermostat, turn a faucet, flick a switch or join a wireless network: without even giving it a second thought.

But did you ever wonder how these vital utilities get to our homes and businesses? Trenchless construction plays an important role in the process.

We’d like to show you how.


TYPES OF TRENCHLESS CONSTRUCTION

HORIZONTAL DIRECTIONAL DRILLING (HDD)

Pipes, conduits and cables are installed using a guided, surface-based drilling rig that creates a pathway underground. The rig then pulls the line through the resulting hole. HDD is suited to longer crossings and can be used to install both large and small diameter product lines. It is not feasible with all geological formations.

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Light HDD Rigs | A smaller, more portable light HDD rig can be used to install lines under shorter crossings. In this example, traffic can continue to flow.

TUNNELING (AUGERING AND BORING)

Tunneling is always done in a straight line, and lends itself to crossings of shorter distances. It can be used to create tunnels of very large diameter (think train or pedestrian tunnels). Tunneling can be completed in a wide variety of geological formations. There are several common tunneling methods. A number of factors will determine which is best suited to a particular project.

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Horizontal Auger Boring | Horizontal Auger Boring is one of the most common tunneling methods. The ground is drilled by an auger as pipe is pushed into the resulting void. Equipment removes the soil and debris as the process proceeds. installed a safe distance below water bodies – protecting the habitat in the event of a spill.

Why trenchless construction?

With the help of trenchless construction, underground pipelines and conduits are installed to provide access to vital utilities in our homes that facilitate modern day life. Let’s take a look at how trenchless construction benefits our life at home.

WHEN YOU DON’T SEE SOMETHING, IT’S EASY NOT TO THINK ABOUT IT.

One of the reasons we give little thought to these utilities is that they are delivered through a network of underground pipelines and conduits. This network of lines brings the utilities from the point of extraction (oil and gas wells, water reservoirs, etc.) to homes and businesses.

For the most part, excavators (diggers and backhoes) dig trenches, where lines are then placed. But what happens if a line needs to go under a busy highway or railway tracks? What if you encounter a river or body of water? What about an environmentally sensitive area?

To some they are obstacles. To us they are crossings.

CROSSINGS | This illustration shows how oil and gas is transported from the well site to refineries & processing stations, and into homes and businesses. Along the way, the lines need to cross obstacles (crossings). This is where trenchless construction comes into play.

THAT’S WHEN YOU CALL IN THE TRENCHLESS CONSTRUCTION EXPERTS.

Imagine if we had to close down a road, freeway, rail system, active utility lines or parkland every time we needed to install or repair a pipeline running underneath! Fortunately, trenchless construction allows us to safely install utility lines with minimal disruption to the public or the environment.

Basically, trenchless construction creates underground tunnels that are slightly larger than the line that is to be installed. The pipeline or conduit is then placed within these tunnels, while the surface remains unaffected.

Less public inconvenience

Roadways, utilities and rail lines can continue operating throughout installation.

Safe installation

Trenchless construction will not affect the structure or integrity of roads, highways, intersecting utilities or water bodies. Pipeline is installed at a safe distance below the surface, calculated for maximum protection.

Reduced costs

The cost of shutting down of existing utility services and transportation routes can be prohibitive and impractical. As could the risk of a spill that occurred by laying a pipeline across the bottom of a river or lake. Trenchless construction provides a safe and efficient solution to both challenges.

Accuracy

Trenchless construction allows lines to be installed with a remarkable degree of accuracy, even over great distances.

TUNNEL BORING / PIPE JACKING

Tunnel Boring and Pipe Jacking Systems are used to hydraulically install underground pipelines up to 4.2 m (168 in) in OD range within strict alignment and grade tolerances. The likelihood of settling or sloughing is very low. Wheel machines are equipped with various cutter heads and sand shelves. A closed-face attachment is available for boring in unstable ground conditions. This versatile system can be easily adapted to work with any jacking pipe, in any pipe joint length. It can accommodate a wide range of pipe diameters.

Tunnel Boring Machines are used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They can bore through hard rock, sand, and almost anything in between. Tunnel diameters can range from 1 m and exceed 15 m (3 ft to 49 ft).

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SLIP BORING

A boring technique commonly used for installing oil & gas pipelines ranging from 51 mm to 1067 mm (2 in to 42 in) in diameter without leaving casing in the ground. Product pipe is welded to steel casings and either pushed or pulled through the ground in sections. The casing is cut off and removed, leaving just the product pipe. Maximum installation length is 150 m (492 ft).

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DOWN THE HOLE HAMMER

A pneumatic hammer is attached to the inside edge of the casing. The front of the DTH breaks cobles, boulders and even solid rock into small pebbles or dust. The spoil makes its way through the hammer and into the casing, where it is removed by airway augers.

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GUIDED BORING

A Guided Boring Machine (GBM) is used to install 305 mm to 3.6 m diameter pipe (12 in to 144 in) with grade and alignment precision. It is commonly used for installations 50 m to 150 m in length (164 ft to 492 ft) or when line and grade accuracy is critical in displaceable soil. Our GBM is extremely versatile and our customers continually approach us with new applications.

The pipe installation involves a two-step process where launch and reception shafts are strategically located to minimize surface disruption. A pilot tube with a theodolite guidance system is then pushed through the ground at the precise grade and alignment specified in the design into the reception shaft. A reaming head is welded to the pilot tube and the casing and the pilot tube is used as a guide to install casing. The GBM can be used in conjunction with auger boring or pipe ramming methodologies.

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PNEUMATIC PIPE RAMMING

Pipe Ramming is used in a wide variety of soil types including gravel, cobble or sand. A pneumatic hammer is attached to the back of the casing pipe and driven through the material at any angle: from horizontal to vertical. The material is cleaned out of the pipe using an auger boring machine. Pipe Ramming methods are used for pipe diameters of 305 mm to 3.6 m (12 in to 144 in).

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