The malfunction is delaying the most ambitious infrastructure project in the city’s recent history. After a 2001 earthquake damaged the Alaskan Way Viaduct, a two-level state highway along Seattle’s waterfront, Washington state set out on a multibillion-dollar project to build a tunnel underneath its largest city, connecting an industrial area near major port facilities with transportation routes that bypass the crowded downtown streets.

SEATTLE — For an entire year, the world’s largest tunnel-boring machine has been stuck deep below this city’s waterfront. Engineers still do not know why ‘‘Bertha,’’ the 326-foot, 2,000-ton behemoth custom built to create a nearly 2-mile tunnel under downtown Seattle, is not working.


Chris Dixon, a top executive at Seattle Tunnel Partners, the contractors group picked to head the project, said last week that an effort to fix Bertha will push the completion date to August 2017, instead of December 2015. And even that may be optimistic.

Supporters of the project include Governor Jay Inslee, Mayor Ed Murray, most of the City Council, and major businesses. But even some of them are beginning to mention the project in the same breath as Boston’s Big Dig, the series of tunnels and bridges that took two decades to build at a cost nearly 10 times initial projections.

‘‘Obviously, it’s very disappointing,’’ said Jean Godden, the City Council member who chairs the Central Waterfront, Seawall, and Alaskan Way Viaduct Replacement Program committee. ‘‘We’re concerned about the disruption during the time that the tunnel construction is underway.’’

Repairing the machine is itself a major undertaking. Bertha, built by the Japanese company Hitachi Zosen Sakai Works, is not able to reverse itself. It has tunneled a little over 1,000 feet into a more than 9,200-foot route, leaving engineers with two options: burrowing into the machine from behind, or tunneling down from above and hauling the whole machine out. They opted to drill down from above.


Engineers have dug a 90-foot hole, three-quarters of the way to the machine. A massive red crane that will drag the malfunctioning front end of the machine to the surface looms next to the Viaduct it will replace. But Bertha is stuck in soft ground just a few feet from the shoreline of Puget Sound, an area that was beneath water until engineers filled it in a century ago, said Joe Mahoney, a professor of construction engineering at the University of Washington. Freeing the machine from that soft ground has required pumping out surrounding groundwater to keep pressure off the hole.

That created problems last month when, in the course of removing ground water, some buildings in the Pioneer Square neighborhood, the oldest in Seattle, sank about an inch, opening cracks in walls and frightening building owners and tenants. Dixon said they would continue digging toward Bertha, but only a few feet at a time, to ensure no further damage.

STP anticipates repairs will be complete by April, when Bertha would be able to continue excavations for the first time in 16 months. ‘‘The uncertainty is how long [repairs are] going to take, because we’re really attempting to do something here that hasn’t been done before,’’ Dixon said.

The decision to move forward on the tunnel came after a decadelong political fight. The state Department of Transportation initially decided, in 2004, to build a conventional ‘‘cut and cover’’ tunnel — digging a tunnel from above like the Big Dig. Voters rejected that, along with another option to rebuild an elevated structure. Local and state officials chose the only remaining option, the bored tunnel, in 2009. The legislature authorized $2.8 billion.


Opponents, including environmental activists, city councilors, former one-term mayor Mike McGinn, and The Stranger, Seattle’s alternative weekly newspaper, have kept up a drumbeat of criticism ever since.

With costs spiraling, some on the City Council are nervous that Seattle could be stuck with the bill. And with Bertha sleeping, some tunnel opponents are reminding supporters of their pessimistic predictions.

‘‘I think we’re at a point today looking forward where people need to be asking, OK, we’ve sunk a lot of money into this. If we get to a point where the contractor isn’t willing to sink any more money in, where do we go from there?’’ said Councilman Michael O’Brien. ‘‘I hear a lot of frustration from folks that they’re not seeing elected officials step up and own up.’’

Other observers see signs the Department of Transportation and Seattle Tunnel Partners are preparing for lawsuits. The DOT is documenting every detail of the delay and the settling around Pioneer Square on its website. On a recent afternoon, survey crews were inspecting the area that had settled, and several blocks north, closer to Seattle’s downtown core.

Elected officials repeatedly invoke safety concerns, which some observers say could indemnify the state against massive cost overruns in a legal case, should the tunnel be mothballed.


‘‘It may be something that it will take some lawyers to figure out,’’ Godden said.

While Bertha is dormant, STP has hastened construction of other parts of the project, like entrance and exit portals. Transportation Secretary Lynn Peterson said this month the project is 70 percent complete, though the boring machine has more than 8,000 feet to go. And until Bertha revs back to life, even STP’s August 2017 estimate is just a guess, based on assumptions that everything goes well in the future.