BOSTON (AP) – Major repairs to the walls of Big Dig tunnels will soon be completed, meaning that, as of the end of the month, the tunnels will no longer be regularly shut down overnight, according to Turnpike Authority chairman Matt Amorello.

The completion of the work, expected next week, will allow officials to open the Interstate 93 tunnels under Boston around the clock for the first time, The Boston Globe reported.

Repair and construction crews have blocked overnight traffic on most weeknights since shortly after the northbound tunnel opened in 2003, said project manager Michael Lewis.

The worst of the leaks, in September 2004, closed portions of the tunnel and led to the disclosure of hundreds more leaks. Big Dig officials have said the leaks didn’t affect the structural integrity of the tunnel and the contractor is paying for the repairs. But the problem drew scrutiny from federal agencies that helped fund the $14.6 billion project.

Officials found that some of the tunnel’s slurry walls had been poured incorrectly, allowing dirt and other debris to get into the concrete. Underground water seeped through that dirt and penetrated the walls or created soft spots.

Four walls are still being fixed, including the section that began leaking in September 2004, Lewis said. He said that wall needs just one more layer of concrete. Three other walls remain under repair, though the work is wrapping up, Lewis said.