In the past, utility pipe installation typically involved open trenching. This process is highly disruptive to the environment but is often considered the most practical. However, in urban landscapes, digging is not always a good option. As underground pipe installation becomes more commonplace, non-disruptive techniques have also become the go-to procedure used by utility contractors.

In general, trenchless technology refers to methods that do not require open-pit digging to install utility pipes. Examples of these methods are tunnelling, horizontal directional drilling, and auger boring. Most horizontal directional drilling companies provide a variety of services supporting some or most of these techniques used to install utility conduits underground.

Horizontal directional drilling

The HDD method makes use of special drill rigs which create the borehole from the surface. The same equipment pulls back the pipe into the bore path created. The drilling involved in this method is minimal and is only used to create the pilot hole and the exit hole. The HDD technique is preferred when the pipes are to pass through a large crossing, or if there are massive obstructions above-ground such as highways, train tracks, rivers, and bridges.

Micro-tunnelling

Micro-tunnelling is another non-disruptive method of pipe laying. The technique uses a tunnelling machine operated above ground to push pipes using the jacking system. As the device removes the soil, the pipes are simultaneously installed into the ground.

Pipe Ramming

This method specifically uses pipes with steel casing. Using a percussion hammer, the pipes are installed by continuously pushing the steel casing forward into the launch shaft until the pipes reach the reception shaft.

Pipe Jacking

This method directly installs pipes using hydraulics. The launch shaft forms a continuous path in the ground where the pipes are pushed. This method requires several workers to manually remove the soil and excavate as the pipes get pushed forward into the desired installation path.

Horizontal Auger Boring

Similar to HDD, horizontal auger boring uses a cutting head that rotates to remove soil and create a bore path. After creating the bore path, the pipe is then pulled back and installed. Although this technique is effective, the steering capability of auger boring machines is limited. This technique is best used when the installation path is short and straight.

Conclusion

Trenchless pipe-laying is valuable to the utility industry because it solves many of the challenges encountered with conventional trenching. Non-disruptive methods of pipe laying make it possible to install complex conduit systems underneath urban landscapes. Trenchless pipe laying is also better for the environment and does not result in groundwater contamination. Moreover, trenchless techniques take up less time and do not require contractors to hire as many workers as they would for the open-pit method.

Nevertheless, there are still some instances when directional drilling or other trenchless techniques are not a viable option. Factors such as ground conditions or soil types are some of the reasons why utility contractors cannot use trenchless techniques to install utility pipes. The open-pit method is still considered a practical alternative when trenchless techniques are not suitable.