Trenchless construction and trenchless rehabilitation are constantly evolving fields. Over the years, various trenchless technologies and innovations have helped to advance this industry, from the introduction of horizontal directional drilling (HDD) to technological advancements in closed-circuit television inspection (CCTVI) camera systems.
Here are some of the emerging technologies that are helping to grow the fields of trenchless construction and trenchless rehabilitation.
Sewer Line Rapid Assessment Tool (SL-RAT)
Cleaning and maintaining pipelines are essential. However, without knowing the existing condition of the pipe, operators and crews can spend valuable time inspecting and cleaning areas that do not need to be cleaned. (Read Trenchless Rehabilitation Evaluation: How to Properly Inspect and Locate Damaged Pipelines.)
To address this, InfoSense Inc. developed a portable on-site condition assessment tool capable of detecting the degree of blockage in gravity-fed sewer systems. Their Sewer Line Rapid Assessment Tool (SL-RAT) system works using acoustic-based technology. The device consists of two crucial components: a transmitter and a receiver, both of which are placed over two adjacent open manholes.
The transmitter sends an acoustic signal down the manhole, which travels through the piping system and intercepted by the receiver located at the other manhole. The system then measures the dissipation of sound energy in the airspace between the two units. Obstructions encountered in the pipe, such as tree roots, grease, debris, or foreign matter will disrupt the sound waves, resulting in an energy gap. (Read The Harmful Effects of Tree Root Infiltration on Potable Water Piping.)
Using this technology, the device can qualitatively identify the level of blockage in the piping system in a matter of minutes. Each result is given a rating between zero and 10, which relates to the degree of obstruction in the segment under consideration. These ratings are based on experience and research with zero indicating substantial blockage, while 10 signifies that the pipe in unobstructed.
One of the major benefits of this technology is that it allows operators to quickly prioritize where and when to focus cleaning efforts. If the tool determines that there are no blockages, cleaning crews can promptly move on to another section of piping without spending time setting up cleaning equipment.
On the other hand, if the tool determines that blockages exist, crews can determine what type of action is required based on the numerical value output by the equipment.
While (Closed-circuit television) CCTV technology has been in use for decades, innovations and enhancements are revolutionizing the way modern trenchless operations are performed. The latest generation of CCTV crawlers are integrated with digital platforms and technologies which make them smarter, more scalable, and more future-proof. (Read Using CCTV to Inspect Pipes.)
For example, some CCTV camera systems have the ability to automatically connect to the internet to download firmware and updates as new features become available. These updates can provide software stability or increase the device’s functionality by adding new features, much like modern smartphones.
New systems are also capable of gathering and reporting various types of information (e.g., pitch, roll, ambient temperatures, humidity, and pressures) via a multitude of onboard sensors. Additionally, since these devices are based on a network control architecture, they are capable of being outfitted with a wide range of accessories, allowing them to adapt to a broader range of trenchless applications.
Much like most digital systems used today, modern CCTV crawlers can also save recorded video to internal memory storage, perform real-time measurements of defects, and automatically upload inspection data to municipal databases and asset management software.
CIPP (Ultraviolet) UV Curing
Another technology set to revolutionize the trenchless rehabilitation industry is UV curing for cured-in-place pipe (CIPP) liners. (Read Why CIPP Is Growing Rapidly for Drinking Water Mains.)
As its name suggests, this type of technology involves using ultraviolet rays to cure (or harden) the resin used in CIPP liners.
Conventional CIPP curing methods use either steam or hot water to cure resin-impregnated felt liners. Both these methods involve heavy vehicles and equipment, such as boiler trucks, which require an extensive workspace. This considerable footprint can cause traffic disruptions and also encroach on private homeowners’ properties.
Furthermore, large vehicles and equipment can make it difficult to operate in hard to reach areas. UV curing, on the other hand, uses lightweight, portable equipment, lessening the impact of CIPP operations on sensitive areas and residential properties.
Additionally, conventional water and steam curing methods can also expose workers and residents to hazardous raw chemicals, forced air, hot steam, and hot water. UV curing significantly reduces or eliminates the release of these harmful emissions.
UV curing is also considerably faster than water and steam curing. Curing operations can take place at speeds of up to five feet of piping per minute. This lessens the time required for rehabilitation procedures and reduces the disruption and downtime of local utilities and services.
Trenchless Pipeline Removal
Trenchless pipeline removal (TPR) provides pipeline owners with a new and innovative way of removing abandoned piping assets. This technique is particularly useful for piping infrastructure that have reached the end of their service life. While current removal methods exist, they are inconvenient and relatively costly.
Removing pipelines using conventional methods involve excavating the surrounding area to expose the pipe under consideration. The pipeline is then cut into several segments for removal and transportation. Finally, the site is reinstated by backfilling and compacting.
Trenchless pipeline removal, on the other hand, involves removing pipelines with minimal excavation or trenching. This proprietary technology, developed by Italian company, Enereco, uses a special helical-cut to reduce the pipeline diameter and reduce skin friction from the extraction process.
Firstly, a cutting machine is inserted into the piping, where a rotating head with a waterjet nozzle sprays high-pressure water capable of cutting through steel. As the device traverses the pipeline, the rotating nozzle cuts the pipe in a helical pattern.
After cutting, an HDD rig applies a pulling force to the pipe. This tension causes the pipe to stretch (like a spring) and reduce in diameter; thus, reducing the skin friction and minimizing the pulling force needed to extract the pipe. After the pipe is removed from its location, the remaining hole is filled with appropriate material.
What We've Learned
This article is by no means meant to be an exhaustive list of innovative trenchless technologies. There are numerous other up and coming tools and techniques that have the potential to change the way we perform trenchless installation and rehabilitation.
As the industry continues to evolve, newer and more advanced technologies are expected to emerge, helping to progress the trenchless sector even further.