Customer Stories

earthworks progress any time by position- ing the SX12, measuring any point, and immediately identifying any underbreak in relation to the driving box perimeter visible on the controller's graphical interface. She has also been creating 3D "profile prints", drawing files that provide the tunnel shape, tunnel boom, driving box, and a numbered position marker for tunnel orienta- tion. Once a section has been blasted or dug out, De Vuyst positions the SX12 and captures a full-dome scan to collect a georeferenced point cloud of the 60-m area. She integrates that data into TBC and using the soware's specialized Tunnel module, she uses a classification tool to automatically clean and process the data to create a tunnel shape—a process that takes 3 minutes per scan. "The scanner captures everything it sees—people, cars, even water droplets—as well as the tunnel shape," says De Vuyst. "Without the automatic classification tool in TBC, I'd have to manually select each bit of noise and delete it. That feature, along with the automatically georeferenced scans, saves me hours of processing time. And because I know I can eliminate noise automatically, I don't worry about passing traffic or objects in the way." Once she has the tunnel shape, she can combine survey controls with the density of points to calculate and verify earthwork volumes as well as convert the 3D model to a tunnel profile drawing, indicating precisely where more sediment needs to be removed and how much. Digger opera- tors then use the prints in their cab as a machine control guide. "I make profile prints of the tunnel at every half meter," says De Vuyst. "That allows everyone to monitor progress at set intervals. Crews can not only see how the tunnel looks now, I can provide historical views to show how the tunnel looked a week ago or even at the beginning of construction. It's incredibly helpful for measuring and monitoring progress." The ability to efficiently produce tunnel profiles was particularly ben- eficial for preparing and positioning Maursund's technical building, which is set in the tunnel center, 93 m below sea level. Teams needed to blast out a space 5 m deep by 20 m long. Precision was paramount because the building's pre-fabricated construction was designed to within only a half-meter of the tunnel wall and the top of two of the building's corners. De Vuyst used the SX12 to as-built and calculate the excavation volumes based on two profile prints for the same area to ensure the space was correct. In early June, crews success- fully constructed the technical building. Locked and bolted In addition to checking and calculating volumes, De Vuyst has also been consumed with bolts—prism bolts, reinforcement bolts, lighting bolts and signage bolts, all of which she has either been taking as-builts of or seing out. Of the roughly 170 bolts she has set out, the most challenging to precisely position were the bolts for road signs that will be De Vuyst uses the SX12 to set out ventilation bolts. The American Surveyor / July/August 2021 22

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