The construction industry, utilities and project managers, as well as the general public, are increasingly becoming more environmentally conscious. While this trend started a number of years ago, it is accelerating. Contractors that can provide a solution that is more environmentally friendly, while also remaining efficient and cost effective, are setting themselves up to lead their competitors. Pipeline installations have the potential to be destructive to the surrounding natural and built environment, but trenchless techniques such as microtunnelling can help mitigate this. Here, we look at the top environmental benefits of microtunnelling.
1. Minimal surface disruption
One of the major differences between traditional open cut methods and trenchless methods such as microtunnelling is the amount of excavation that needs to take place.
“Traditional open cut methods require a large amount of excavation as trenches need to be dug along the entire length of the pipeline route. This results in a large amount of environmental disruption to flora and fauna, and can be disruptive to the community depending on the location and route,” Stuart Harrison, Managing Director, Edge Underground, said.
“Trenchless methods don’t have this problem as they require minimal excavation – for microtunnelling only a small entry and exit pit at each end of the pipeline needs to be excavated, and the ground between these points is left undisturbed.
“This drastically reduced site footprint means there is less impact to the surrounding environment, flora and fauna.”
2. Spoil management
Spoil management and disposal is critical to any pipeline construction project to meet environmental regulations. Due to the amount of excavation that is required for open cut installations, mounds of spoil either need to sit at the site or be trucked out during works and trucked back in for backfilling, and in cases where there is ground contamination, it needs to be disposed of correctly.
On the other hand, microtunnelling requires much smaller quantities of incoming and out materials as less excavation is needed.
“Some microtunnelling machines, such as the AXIS laser guided boring system, use vacuum excavation, which offers improved environmental outcomes,” Mr Harrison said.
“The vacuum excavation method utilises a vacuum tank and power unit to help maintain a clean site. During drilling, upon reaching the launch pit, the spoil transitions from the drill casing to a hose that runs up the launch pit to the tank.
“Amongst other benefits, this eliminates the need to manually handle spoil within the launch pit, which not only reduces manual labour but also provides a cleaner and safer pit environment for personnel to work in.
“There is also a cost-saving benefit of using the vacuum excavation method, as it is able to remove the spoil as it is produced, removing the need to suspend drilling operations so it can be done manually. This reduces project costs and helps ensure the pipeline is completed on time.”
3. A safe working environment
As microtunnelling requires fewer trenches and uses vacuum excavation methods, it also has the benefit of helping to create a safer working environment.
Working within or near excavation works are considered dangerous due to the risk of potential cave-ins which can limit workers’ ability to escape and of objects falling into the excavated area. These risks increase the deeper the excavation is.
As microtunnelling only requires an entry and exit pit to be excavated, the risks are much lower as works are contained to a smaller area than for open cut installations.
4. Reduced emissions
Construction activities are one of the main contributors to a country’s overall emissions of greenhouse gases. Both open cut and trenchless pipeline installations contribute to this as well.
“The AXIS is the only microtunnelling machine on the market that has been proven to have low carbon emissions,” Mr Harrison said.
“During a project in the US which used the AXIS system, Dr Sam Ariaratnam and his team from Arizona State University undertook an emissions study using the ‘E Calc’ emissions calculator. The study compared the results to alternative methods, and the AXIS system conclusively had the least emissions of all of them.
“With countries working towards reducing their overall emissions, the AXIS is able to help project managers and contractors reduce their project carbon footprint.”