Harper Brothers Construction and HB Trenchless recently launched a new Akkerman 96-in. earth pressure balance tunnel-boring machine as part of the Houston Public Works Surface Water Transmission Program. The machine will excavate an 874-ft-long tunnel under IH-69 (US-59) in downtown Houston. The crane is positioned to lower the TBM about 75 ft into the concrete secant pile shaft at the intersection of Clay and Hamilton streets. 

Operating a DJI Phantom 4 Pro V2.0 drone, Byland aimed to capture the completed tunnel—“especially the lower third of the shaft when the concrete ring beams were installed to make the shaft watertight.” He also wanted to highlight the breakout structure, “which is the flat section of concrete wall at 12 o’clock,” he says. “It was an overcast day, which is perfect lighting for looking into shafts from the air. If it’s too sunny, the ground surface is too bright and the shaft just becomes a black void if its more than about 15 ft deep—and this shaft is about 75 ft deep. It’s rare that all the elements line up on a particular day to get a shot like this of work both above and below ground.”