The City of Seattle embarked on a $2.1B infrastructure project to replace the Alaskan Way Viaduct with a 1.7-mile-long, 57-foot-diameter tunnel. However, the project faced significant challenges when the world’s largest tunnel boring machine, “Big Bertha,” encountered operational issues, leading to ground settlement and visible damage to neighboring buildings. Extensive groundwater pumping exacerbated the situation, culminating in a large sinkhole formation near the recovery pit in January 2016, prompting a temporary shutdown of the project.