West Gates DIW Pond Expansion

Completed in 2024 by Southland Contracting, the West Gates DIW Pond Expansion Project began beneath Taxiway Whiskey Alpha (WA) / Bravo 4 (B4) in April 2023. A 60-inch manned Single Shield Tunnel Boring Machine (TBM) excavated a 1,465 linear foot tunnel for a two-pass installation. This tunnel was reinforced with steel casing and included an intermediate jacking station. Simultaneously, SCI’s second tunnel crew began setting up and excavated a 43-foot-deep launch shaft in May 2023. The 38-foot diameter launch shaft was supported by steel ribs and wood lagging for a single-pass installation. This 550 linear foot tunnel, situated northwest of Taxiway Charlie November (CN), was excavated using a manned 96-inch diameter Single Shield TBM. The single-pass installation involved the direct jacking of FRP pipe. A 45-foot diameter common reception shaft was installed and supported with steel beams and wood lagging. This common reception shaft connected the waste flow from the 550 linear foot single-pass installation to the downstream 2,051 linear foot tunnel crossing beneath Runway 16 Lima / 34 Romeo (16L/34R). Upon completion of the WA/B4 and CN projects, Maverick mobilized for a two-pass, 2,051 linear foot tunnel beneath Runway 16L/34R. Maverick, a manned 132-inch diameter Single Shield TBM, accommodated a 72-inch DIW drain line, two 32-inch DIW High Concentrate drain lines, an 8-inch Glycol Supply line, two 14-inch conveyance pipes, as well as electrical and communication lines. The excavation was reinforced with steel ribs and channel lagging, and the depth of the 45-foot diameter common reception shaft reached 50 feet. Trench boxes were employed at the launch pit due to the shallow depth at this location. The remaining three bores were subcontracted to a local firm, Underground Infrastructure Technology (UIT). These bores varied in diameter from 30 inches to 48 inches and totaled 1,113 linear feet. UIT initiated their first bore at 88th Avenue in May 2023.