How Can Underground Utilities Benefit From 3D Laser Scanning?

By Emily Newton

Contractors and utility workers need detailed and specific information when working with underground utilities. However, it’s not uncommon for key data sources to be maps and topological surveys that are inaccurate, outdated, or incomplete.

Scanning technology, like photogrammetry and ground-penetrating radar, are commonly used to supplement these data sources, providing better information on projects and surroundings.

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New scanning techniques are starting to revolutionize how workers map and model underground infrastructure. Innovations like 3D laser scanning provide workers with a clearer picture of underground utilities, making construction easier, safer, and more straightforward.

What Is 3D Laser Scanning?

3D laser scanning (or LiDAR) is a non-contact, non-destructive method for using lasers to capture the shape of a physical object. At their simplest, these systems consist of two components: a laser and a camera.

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Information from the lasers is stored as a point cloud — a collection of millions of individual points representing areas where the lasers made contact with an object.

Using point cloud processing software, workers can transform this data into a model of the object or area scanned. Workers can then import this model into CAD software.

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In a land survey, for example, the 3D scan would provide a topographic model of the area scanned. The tech can also be used in construction to scan for surface-level structures.

Typically, these systems use infrared lasers to capture information on structures. These lasers can also penetrate both the ground and vegetation to an extent. They can also be used day or night. To measure underwater structures or surfaces, workers can use a technique called bathymetric laser or LiDAR scanning. This technique uses green light instead of an infrared laser.

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How Is 3D Laser Scanning Used?

Current advanced laser technology enables a high density of points, meaning they can yield highly detailed models of scanned objects or areas. Intricate or complex structures can be captured accurately using the technology, making it a good fit for construction work that requires high levels of accuracy in site models.

For example, one common use case of LiDAR is in scanning equipment used in oil and gas production. Storage facilities, like tanks, need to be regularly strapped — or inspected to calibrate the facility’s dimensions and verify its roundness. Many businesses use LiDAR in gathering tank strapping information, along with other use cases like equipment inspection, volume verification, and topographical scanning for expansion planning.

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Other everyday use cases include sunshine analysis in agriculture, resource monitoring by land managers, and no-contact structure scanning by archeologists.

Laser scanning is also common in cutting-edge applications — NASA’s “Perseverance” rover, for example, uses lasers to capture geological information from the surface of Mars.

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Integration With Other Technology

LiDAR technology is often deployed in combination with other systems that capture information on surface-level or underground structures, like GPS, electromagnetic locators (EMLs), and ground-penetrating radar (GPR) systems.

Many modern LiDAR systems bundle in these ground-penetrating scanning technologies, providing a combination of laser scanning and GPR systems that can fully map an area.

These integrations can provide workers with a combination of above-ground data and underground structures needed to move forward on a utility project. Information from LiDAR and other systems can be automatically coordinated, making it simpler for contractors to create a single cohesive model of an underground utility work site from multiple data sources.

Key Benefits of Laser Scanning

Laser scanning technology offers a few essential benefits over other scanning technology that can make it preferable for underground utility workers.

1. Speed and Scan Efficiency

LiDAR is fast, especially when compared with other popular scanning methods, like photogrammetry. Modern LiDAR systems can scan faster than a bullet travels, meaning large amounts of data can be gathered extremely quickly.

Many modern LiDAR systems also integrate GPR, meaning it’s possible to capture surface data, structure data, and underground utility data simultaneously. This can help make the scanning process much more efficient.

This speed and efficiency are why LiDAR scanning technology is widely used in a range of construction fields.

2. High Levels of System Mobility

Many modern LiDAR systems can operate while affixed to vehicles. The vehicle operator drives around the scan area, and the LiDAR system scans without needing to be set up multiple times to capture data on the scan area.

A GNSS system, like GPS, coordinates with the LiDAR system, allowing it to continuously organize data as it moves. This enables extremely efficient capture of site data. Often, one button press may be enough to capture all the data a project needs.

This approach enables workers to capture survey-level location data as well as additional information — like depth of cover, weld spots, and the location of nearby utilities.

3. Access and Reach

LiDAR technology can reach areas that other scanning methods can’t. This can both make it easier to scan utility job sites and helps mitigate some of the safety risks associated with scanning. If an area is dangerous or difficult to access, technology can help make scanning the area faster and safer.

For example, underground chambers may be difficult or impossible for human workers to access. LiDAR scanners can be lowered into the chamber or scan from a surface-level access point. Information from the scan can provide a detailed picture of the room quickly and safely.

4. Data Accuracy

Modern LiDAR systems can capture highly detailed scans of a site or structure — building point clouds that can contain millions of points. This extreme accuracy makes the technology extremely useful when precision is necessary — as in underground utility work.

The high accuracy of LiDAR tools means they can also effectively scan complex geometries. As a result, the technology is often an excellent fit for projects that require scans of intricate equipment or structures.

5. Non-Contact and Non-Destructive

Importantly, LiDAR systems can scan a surface without touching or damaging it. They can also work in the dark, meaning they may require minimal support from other construction equipment, like lighting rigs. The use of LiDAR can help to reduce to impact that scanning has on a structure.

Using 3D Laser Scanning to Support Underground Utility Work

Laser scanning can provide construction workers with detailed information on a variety of surfaces. Workers can use this technology in conjunction with tools like GPR, allowing them to quickly collect information on a utility project work site.

Compared to other scanning methods, LiDAR is fast, mobile, and accurate, making it an effective choice for utility workers and contractors who need more information on the utilities they are working on.

Emily Newton is a construction and industrial journalist. She is also the Editor-in-Chief for Revolutionized Magazine. Keep up with Emily by following her by subscribing to Revolutionized’s Newsletter.